High End Performance
Printed From: CorrectCraftFan.com
Category: Repairs and Maintenance
Forum Name: Engine Repair
Forum Discription: Engine problems and solutions
URL: http://www.CorrectCraftFan.com/forum/forum_posts.asp?TID=6594
Printed Date: November-24-2024 at 5:23pm
Topic: High End Performance
Posted By: Nautique2001
Subject: High End Performance
Date Posted: May-07-2007 at 4:10pm
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I'm trying to piece together 100's of older threads regarding high end engine performance. Could somebody just quickly give their input on this:
My rebuilt 351 engine has about 22 hours on it. The Holley carburetor is new, all electrical components are new. Hoses, filters, gas related stuff new. I think the only original parts are the starter and alternator. Fresh gas, 89 octane in tank too. At about 4,000 RPM's, I'm starting to run out of throttle fast. The tach reads about 4,250-4,300 TOPS, WOT with a new ACME 540. Listening to the engine and feeling what the boat is doing, my only conclusion is that I'm lacking sufficent fuel to the engine. I haven't checked the timing at high end yet. I've been reading stuff through out. What am I looking for the timing to be at 4,400 RPM's? The manual says no more than 30 degrees BTC. So does this mean 29 BTC is OK? Will adjusting the carburetor and timing cure lacking RPM's? The wacky thing is that when I have the throttle pinned, I'll be at about 3,800 RPM's then all of a sudden the engine adjusts it's RPM's to hit about 4,250. Everything else sounds and runs extremely healthy, except for the high 3,000, low 4,000 RPM band. I hate to repeat prior thread inquiries, but quick, short replies would really help. Thanks, Ken ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=1052&sort=&pagenum=4&yrstart=1986&yrend=1990" rel="nofollow - Nautique 2001 |
Replies:
Posted By: nuttyskier2002
Date Posted: May-07-2007 at 6:17pm
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You say your prop is new. So how new? I mean is there any history of your engine turning any higher than 4300 RPMs with this prop? Also, there's nothing wrong with a 4300 RPM WOT. What I'd be concerned with is the sudden gain from 3800 to 4250. This sounds like something is slipping - Either the prop or the transmission. But more likely the prop (if it's not cupped). What speed are you reaching?
To answer the question about timing, max timing advance should be reached by 3000 RPM. With the stock distributor, base timing will be 10 deg BTDC (screw down cap) and end up somewhere around 28 - 32 deg BTDC @ 3000 RPM. Some guys here have posted that they have achieved better performance by re-curving their timing advance to reach 35 - 37 deg @ 3000 RPM. I'd be very careful in trying this. Good luck and please post your results. Brian ------------- 95 Malibu Echelon w/Mercruiser 350 Magnum Skier Former boats: 88 Ski Centurion Tru Trac II 59 Chris Craft Capri (woody) |
Posted By: Munday
Date Posted: May-07-2007 at 7:06pm
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It could be stuck advanxe or just plain wrong advance in distributer.or even sticky secondaries.
Munday |
Posted By: 79nautique
Date Posted: May-07-2007 at 7:11pm
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Ken
you should see max advance by 2500 and no latter than 3000 rpm at around 30-35 the more the better as long as it doesn't ping on the top end. I would focus on the fuel pump makes sure you have a constant 5 lbs of pressure and also check the carb, it will need tweeked regardless if it was just re-built or new out of the box, it is a 600 cfm model correct?. To me it sounds like you have an issue with the secondary's on the carb or maybe a 2.5 power valve in it. might even be too small of jets on the secondary side as well. ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=756&sort=&pagenum=1&yrstart=1979&yrend=1979 - 79 nautique |
Posted By: TRBenj
Date Posted: May-07-2007 at 8:33pm
The secondaries on a stock 4160 wont have jets, only the metering plate. Nutty, I dont think 4300 RPM sounds right. A stock 351w in a 2001 should be turning a 540 closer to 4600 RPM. From what I remember, Ken was turning his previous 4-blade 4100-4200 RPM, so the problem was there before the swap. ------------- |
79nautique wrote:Posted By: 79nautique
Date Posted: May-07-2007 at 11:37pm
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tim don't believe ken stated what carb he bought to start with so was listing all possible options to look at encase he does have a model that has secondary jets. ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=756&sort=&pagenum=1&yrstart=1979&yrend=1979 - 79 nautique |
Posted By: Nautique2001
Date Posted: May-08-2007 at 11:52am
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Thanks for the input. I'm not looking to push the engine beyond the factory specs. I'd like to be able to reach the maximum performance specs of 4,400 RPM.
The ACME is brand new and recently tuned. I have a Holley carburetor, which has 22 hours on it. It has "High Performance" stamped on the side of it, I'm not sure of the model number. Does an engine go out of original adjustment after the break in period? I haven't verified the timing since it was installed in late 2005. Tim's exactly right, my four blade OJ wasn't spinning up to the max RPM range. I actually had OJ make adjustments to give me more RPMs, as I was spinning 3,800 max when I got it. Since the new "rebuilt" was installed, I've never reached maximum RPM, 4,400. It could be an adjustment that needs to make all the difference. Ken ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=1052&sort=&pagenum=4&yrstart=1986&yrend=1990" rel="nofollow - Nautique 2001 |
Posted By: 79nautique
Date Posted: May-08-2007 at 12:03pm
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the carb number would help more than knowing it say's high performance on the side. And yes the timing needs re-checked the timing chain will stretch and you need to check what the advance is at 2500 rpm as well. You will also need to dial in the carb as well it's not a bolt on without any adjustment needed type part and it goes way beyond setting the idle mixture screws, choke stat, and idle settings. ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=756&sort=&pagenum=1&yrstart=1979&yrend=1979 - 79 nautique |
Posted By: Nautique2001
Date Posted: May-08-2007 at 12:03pm
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Tim,
I just shot an e-mail off to you and Brad about using my boat tonight. I want to grab my Dad's timing light and see what we have for settings. I can be the boat of choice for this evenings pull. Ken ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=1052&sort=&pagenum=4&yrstart=1986&yrend=1990" rel="nofollow - Nautique 2001 |
Posted By: Nautique2001
Date Posted: May-08-2007 at 12:06pm
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Thanks, Chris. My boat wasn't lake tested after Correct Craft installed the new motor. I'm sure I have some adjustments that are necessary at this point in time. I've seen how bad timing throws off the entire program with performance. I'm actually going to go get my boat during my lunch break and grab the numbers off the carb. I'll let you know.
Thanks ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=1052&sort=&pagenum=4&yrstart=1986&yrend=1990" rel="nofollow - Nautique 2001 |
Posted By: Hollywood
Date Posted: May-08-2007 at 12:16pm
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Ken I'm going through pretty much exactly what you are with our '88.
I couldn't get more than 4300 rpm with a 12" pitched prop. The stock 13" pitch brought me back down to 4150 rpm at WOT. I wouldn't be concerned with what the tach is telling me except that's at a GPS verified 38 mph. I've checked the throttle cable and looks like it's properly adjusted. Timing chain feels tight. I will keep you posted although it sounds like you're attacking your issues sooner than I will be. Boat will probably hit the water next weekend for fuel pressure and timing checks. Going down to TX to take a few sets behind Feelgood's BFN this weekend. Hopefully I can learn a few things from this thread when I get back. I have an unknown EI conversion that uses a ballast resistor and an oil filled coil. Magicman's tuned 4160 is ready to bolt on for testing as well. Just put in fresh plugs and fuel filter. ------------- |
Posted By: Nautique2001
Date Posted: May-08-2007 at 12:27pm
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Hollywood,
Pretty mind boggling issue. The engine runs like a top until you hit the high 3,000 RPM band. I'm sure you feel the loss of throttle response like I do from 4,000 to about 4,300. I never thought to check the position on the throttle cable. I'm pretty positive the timing and carburetor adjustments aren't jiving. I think we'll start by advancing the timing a couple of degrees and turning the two adjustment screws a quarter towards the open position. I don't think the prop has anything to do with the lack of RPM's. I'll post something tomorrow. Ken ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=1052&sort=&pagenum=4&yrstart=1986&yrend=1990" rel="nofollow - Nautique 2001 |
Posted By: TRBenj
Date Posted: May-08-2007 at 12:33pm
Ken, I saw your email. If you get a chance, grab the List number off the choke horn. It should be somewhere around here:
Im assuming its a stock 351w replacement either from SkiDIM or Correct Craft, so it should be a 600 CFM 4160. The Holley tech line will be able to ID it for sure based on the List #. Its quick and easy to dial in the timing. We can verify youre getting full advance- it sounds like the stock dist should be getting 20-24 degrees on top of the base (can anyone verify that number?). Based on what youre seeing though, Im with Chris and think there may be an issue with the secondaries. Beyond that, I couldnt tell you what to adjust. ------------- |
Posted By: Nautique2001
Date Posted: May-08-2007 at 12:41pm
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Tim,
I'm going to Natick to go pick up my boat and timing light. I'll get you those numbers. What about the accelerator linkage piece that opens the secondaries? Can that be adjusted to let more fuel in? Tim, we also need to check the throttle linkage to ensure I'm getting max throttle. This is a 22 hour carburetor, so I assume it's not wear and tear. Ken ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=1052&sort=&pagenum=4&yrstart=1986&yrend=1990" rel="nofollow - Nautique 2001 |
Posted By: GottaSki
Date Posted: May-08-2007 at 1:32pm
No. That closes the secondaries
always a valid check ------------- "There is nothing, absolutely nothing, half so much worthwhile as messing around with boats...simply messing." River Rat to Mole |
Posted By: bkhallpass
Date Posted: May-08-2007 at 2:19pm
Sounds like Ken and Hollywood have lemons. Tell you what, I'll give you $2500 a piece for them, and I'll even get them back to CA at my expense. You can use the money for a down payment on a shiny new boat with all the power you need. Just trying to help a brother out. BKH------------- Livin' the Dream |
Posted By: 79nautique
Date Posted: May-08-2007 at 2:33pm
wouldn't do that at all you do not have a rough idle issue and adjusting the screw will not effect off idle performance like your having. Check the cable adjustment first to verify WOT at the carb, then move to the timing set it at 8-10 inital and then see what the timing is at 2500 rpm should be around 30 degrees after that you need to focus on fuel delivery and when and if the secondaries are opening. Kevin, I'll be in the countryside area? electromotive diesel plant next week and I might be able to stop by and help you out if you want. ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=756&sort=&pagenum=1&yrstart=1979&yrend=1979 - 79 nautique |
Posted By: backfoot100
Date Posted: May-08-2007 at 2:39pm
Ken, these are the idle mixture screws. Adjusting those won't do a thing for the WOT issues that you're having. One thing to check is to take a paper clip and put it on the secondaries linkage. Take a run at WOT and as the secondaries open up, the paper clip will slide along the linkage and stay there when you throttle down. You can manually open the secondaries (with the engine off obviously) then and verify that they are opening all the way. Also pull your plugs and check them to make sure that you're not running too lean or rich. You again take a run at WOT for a few seconds and just turn off the engine before you throttle back. That will ensure that you get a good indicator of the plugs at WOT and not idle or mid-range. |
Posted By: backfoot100
Date Posted: May-08-2007 at 2:39pm
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Posted By: Hollywood
Date Posted: May-08-2007 at 3:25pm
Thanks Chris, I would take you up on that offer except I will be out of town all of next week, as well as most of the week following. I will be buttoning up the boat tomorrow night to get ready to run which won't be until the 19th. This is an embarassingly late start for us, although I have been skiing several times this year already. ------------- |
Posted By: Nautique2001
Date Posted: May-08-2007 at 3:27pm
I just took a couple of pics. Not sure if this helps determine which model it is:
 ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=1052&sort=&pagenum=4&yrstart=1986&yrend=1990" rel="nofollow - Nautique 2001 |
Posted By: Hollywood
Date Posted: May-08-2007 at 3:29pm
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Pull off the arrestor and get the damn numbers off the air horn already. ------------- |
Posted By: Nautique2001
Date Posted: May-08-2007 at 3:31pm
Brian, I'll trade you straight up! ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=1052&sort=&pagenum=4&yrstart=1986&yrend=1990" rel="nofollow - Nautique 2001 |
Posted By: Nautique2001
Date Posted: May-08-2007 at 3:32pm
Be right back, I'll go grab a wrench... ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=1052&sort=&pagenum=4&yrstart=1986&yrend=1990" rel="nofollow - Nautique 2001 |
Posted By: MaddMarxx
Date Posted: May-08-2007 at 3:47pm
| Try not to drop the nut down the carburetor... |
Posted By: Nautique2001
Date Posted: May-08-2007 at 3:50pm
Ooops. Kidding... SAE J1223 75009-3 1195 ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=1052&sort=&pagenum=4&yrstart=1986&yrend=1990" rel="nofollow - Nautique 2001 |
Posted By: Hollywood
Date Posted: May-08-2007 at 3:51pm
MM, you don't know the difference betwen a nut and a bolt? I would expect that from blondie but not you. 
I also forgot to mention how much I like the looks of that annodized arrester. Classy.
------------- |
Posted By: Nautique2001
Date Posted: May-08-2007 at 4:03pm
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You like the gold look? Gives it a little pop.
So is the 4160 a decent carburetor? I just need the thing to spew as much fuel as possible at WOT. What's the trick with this little monkey? We'll be on the lake in T=90 minutes.... Ken ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=1052&sort=&pagenum=4&yrstart=1986&yrend=1990" rel="nofollow - Nautique 2001 |
Posted By: TRBenj
Date Posted: May-08-2007 at 4:04pm
Holley tech says its a marine 4160 with vaccuum secondaries, 600cfm (just like we thought). ------------- |
Posted By: Nautique2001
Date Posted: May-08-2007 at 4:08pm
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Tim, I hope you're taking notes here. Hopefully it's something simple.
Maybe this woman is hidding in our bows, Hollywood.  ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=1052&sort=&pagenum=4&yrstart=1986&yrend=1990" rel="nofollow - Nautique 2001 |
Posted By: GottaSki
Date Posted: May-08-2007 at 8:00pm
great googaly moogaly
there are about 4160 different 4160 carbs, bare the air horn, give up the list number and take a picture. tricks, plural, and too many to list. ------------- "There is nothing, absolutely nothing, half so much worthwhile as messing around with boats...simply messing." River Rat to Mole |
Posted By: BlondieGurl1443
Date Posted: May-08-2007 at 8:01pm
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Is that what you call a "twin Boob-balist" system! It will make a wake sooo big you wont even need a rope!!!!!!
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Posted By: 6strings
Date Posted: May-08-2007 at 10:58pm
| Whoa! We do like boobs here but not quite that big! Please! |
Posted By: Jim_In_Houston
Date Posted: May-08-2007 at 11:09pm
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Hey! That's my wife!!!!!!!!!! Where did you get that picture? ------------- Happy owner of a '66 and a '68 Mustang |
Posted By: 6strings
Date Posted: May-08-2007 at 11:11pm
| Oops! Sorry about my comments Jim.... |
Posted By: Nautique2001
Date Posted: May-09-2007 at 9:40am
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Here's a summary of last nights run.
Timing - Perfect Throttle cable - Perfect (minor adj. by Tim) Tim and Brad put there minds together as we went from a quick 600 RPMs, up to 4,800 RPMs. We stayed at about 4,800 RPMs for about five seconds max and the engine RPMs dropped on their own to 4,100. Tim and Brad were confident the float in the secondary is out of adjustment. They bent something in the float and put it back together. We saw a 200 RPM increase and it stayed in the higher RPM band longer before backing down. We then ran out of light, so we packed it in. Does anyone know of a way to judge the distance of the float adjustment to get it right on? We still have some work to do. Here's a video from last night, thanks to Brad's new video camera. Listen closely to the RPM's. Can you tell when it drops? http://s112.photobucket.com/albums/n162/barracuda_brad/Videos/?action=view¤t=M2U00011.flv - Engine RPMs dropping Ken ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=1052&sort=&pagenum=4&yrstart=1986&yrend=1990" rel="nofollow - Nautique 2001 |
Posted By: 79nautique
Date Posted: May-09-2007 at 9:56am
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My dad alway's uses a T-shaped scale/ruler to measure the float height, it's basicly two scales with a u-shaped bracket with a thumb screw so that on scale can slide and be set a set distance and the other scale is mainly for resting on a surface for a reference point. I'll try and see if summit or jegs has one to show you what I'm talking about.
Have you change the fuel/water seperator lately and what about the check ball in the vent of the gas tank? ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=756&sort=&pagenum=1&yrstart=1979&yrend=1979 - 79 nautique |
Posted By: TRBenj
Date Posted: May-09-2007 at 10:06am
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It should be pretty obvious from the video when the rear bowl runs out of fuel- Ken isnt backing off the throttle and it slowly drops from about 4800 to 4200 RPM.
The secondaries appear to be functioning properly- they come in at the right time and stay open (even when the RPM's decrease). No stumbling or other driveability problems. If you back off on the throttle and give the rear bowl a little time to fill, the motor will achieve a higher RPM when you go back to WOT (until it runs out again). Like Ken said, the timing is fine (advances from 6 degrees at idle to about 27 degrees at 3000 RPM). Throttle cable is getting full range. It just wont hold 4800 RPM. We raised the rear float level and it appears to have improved performance. Ken said that sustained WOT RPM's increased from 3900 to 4200 with the float adjustment, so it appears we're on the right track. We didnt have a scientific way to adjust the float- just bending the arm a little at a time and using trial and error. Im also wondering if it could still be a fuel pressure issue. Is there an easy way to measure in-line pressure with the hard fuel line? Any other thoughts? Edit: Im too slow with my reply. Chris, did you watch the video? It performs great out of the hole and at WOT until the rear bowl runs dry. Not sure where that float should be adjusted- does it look like it should be raised more or is it more likely a fuel pressure problem? Maybe we need more info to tell. I should also thank ReidP and his buddy Todd for their help on the phone last night! ------------- |
Posted By: 79nautique
Date Posted: May-09-2007 at 10:13am
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if it was fuel pressure issue that would show way earlier than after it's peaked max rpm. timing is a little low though I would bump it up two degrees or more if it doesn't ping. ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=756&sort=&pagenum=1&yrstart=1979&yrend=1979 - 79 nautique |
Posted By: Nautique2001
Date Posted: May-09-2007 at 10:14am
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Chris,
I haven't checked the check valve in the fuel line. Good idea. Page 49 of the PCM service manual indicates that a specific toll is necessary for the adjustment to the float, Kent-Moore J10193. I Googled, carburetor adjustment tools. Here's one site I found http://www.thecarburetorshop.com/Carbshop_tools.htm#Holley - Tools . Tim, I'll give Vincent a call at SKIDIM. Maybe we can check the check valve in the line too? ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=1052&sort=&pagenum=4&yrstart=1986&yrend=1990" rel="nofollow - Nautique 2001 |
Posted By: Nautique2001
Date Posted: May-09-2007 at 10:18am
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Tim,
I think next round of tweeking, we really need that Holley ajustment tool. We saw how tweeking too far one way throws off the entire show. You and Brad did pretty well by eye though. Ken ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=1052&sort=&pagenum=4&yrstart=1986&yrend=1990" rel="nofollow - Nautique 2001 |
Posted By: 79nautique
Date Posted: May-09-2007 at 10:24am
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screw the tool raise it a little more bye sight if you go too much then bend it back slightly. ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=756&sort=&pagenum=1&yrstart=1979&yrend=1979 - 79 nautique |
Posted By: TRBenj
Date Posted: May-09-2007 at 10:31am
Thats my thought. The only problem is that with the bowl sitting flat (looking down at the open bowl), we moved the top of the float from 3/16" away from the top to within 1/8". This is where we saw an improvement. Once it hits the top of the bowl, theres no easy way to gauge any changes. Our first adjustment had the float up against the bowl (with too much tension on it) and the carb was just dumping gas at idle. Sounds like trial and error is the way to go? ------------- |
Posted By: 79nautique
Date Posted: May-09-2007 at 10:47am
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or you might need to raise the primary float slightly as well. ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=756&sort=&pagenum=1&yrstart=1979&yrend=1979 - 79 nautique |
Posted By: TRBenj
Date Posted: May-09-2007 at 10:53am
I take it the primary float level can effect the secondaries? When installing a new carb on one of these boats, I know float adjustments are usually necessary- would it be common to have to raise both the front and rear due to the angle? ------------- |
Posted By: 79nautique
Date Posted: May-09-2007 at 11:11am
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won't the primary float control weather or not fuel is entering the carb before the secondary even comes into play? ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=756&sort=&pagenum=1&yrstart=1979&yrend=1979 - 79 nautique |
Posted By: Nautique2001
Date Posted: May-09-2007 at 11:31am
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Here's a response from Correct Craft:
Sounds like fuel starvation problem. Try running the engine off of a 6 Gallon OB tank hooked to the fuel pump and see if it does the same thing. ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=1052&sort=&pagenum=4&yrstart=1986&yrend=1990" rel="nofollow - Nautique 2001 |
Posted By: JoeinNY
Date Posted: May-09-2007 at 11:40am
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I tend to agree with the stavation problem, float adjustment is important but if it was as touchy as you guys are making it seem this thing would never make it around a corner. This boat is running like a boat that has been sleeping too long too often and has crud in the system. ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=1477 - 1983 Ski Nautique 2001 1967 Mustang 302 "Decoy" http://www.youtube.com/watch?v=cO5MkcBXBBs - Holeshot Video |
Posted By: Nautique2001
Date Posted: May-09-2007 at 11:46am
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The fuel tank was inspected a year ago for crap and sediment. It's clean. New fuel hoses and filters. I do need to start putting more hours on it though, keep everything flowing.
Ken ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=1052&sort=&pagenum=4&yrstart=1986&yrend=1990" rel="nofollow - Nautique 2001 |
Posted By: Nautique2001
Date Posted: May-09-2007 at 11:51am
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One more question, would the pitch of the prop have an effect on top end? Maybe it bites in better after plaining and loses RPM. Should I slap on the factory 13X13 to see what happens?
Ken ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=1052&sort=&pagenum=4&yrstart=1986&yrend=1990" rel="nofollow - Nautique 2001 |
Posted By: 79nautique
Date Posted: May-09-2007 at 12:03pm
no you would never get the rpm to start with ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=756&sort=&pagenum=1&yrstart=1979&yrend=1979 - 79 nautique |
Posted By: Nautique2001
Date Posted: May-09-2007 at 12:06pm
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Got ya. What do you think of Correct Craft's idea with filling an O/B motor gas tank and running the fuel line directly to that?
Ken ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=1052&sort=&pagenum=4&yrstart=1986&yrend=1990" rel="nofollow - Nautique 2001 |
Posted By: 79nautique
Date Posted: May-09-2007 at 12:06pm
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bump the timing up two degrees and raise the primary float 1/16" , your almost to the point of nit picking it too much. ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=756&sort=&pagenum=1&yrstart=1979&yrend=1979 - 79 nautique |
Posted By: 79nautique
Date Posted: May-09-2007 at 12:08pm
waiste of time if it was fuel starvation issue you would never see the top rpm to start with. Change the timing raise the float and be done with it. ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=756&sort=&pagenum=1&yrstart=1979&yrend=1979 - 79 nautique |
Posted By: 79nautique
Date Posted: May-09-2007 at 12:25pm
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the more think about this and look through the reference section, you have an electronic ignition or at least conv. kit correct?
and your timing is set at 6 btdc and a 27 at 3k both which are low, change the timing to 10 btdc then run the boat and see how it perfoms if it doesn't ping leave it there if it ping's set it a 8 btdc. ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=756&sort=&pagenum=1&yrstart=1979&yrend=1979 - 79 nautique |
Posted By: TRBenj
Date Posted: May-09-2007 at 12:45pm
Was this another NECC job, Ken? I wouldnt say we're nitpicking, Chris- just trying to narrow down the problem. I agree that the timing is low, but it starts and idles well, advances properly and gets the boat to 4800 RPM. The secondaries are obviously starving at sustained WOT running- could that be caused by a 20-30% decrease in flow to the pump? The secondaries are initally fine as you can see in the video- its just that the bowl empties faster than it can refill. Im certainly not ruling out the float adjustment, just saying it may not be the only thing to look at. ------------- |
Posted By: 79nautique
Date Posted: May-09-2007 at 12:52pm
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put more timing into it first easiest thing to do to start with, run it then if it is still coming back on the rpm raise the front float 1/16", it's not a double pump carb so the primary float effects the secondary float on a single inlet holley, really suprised there's a second float on a single inlet model to start with. ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=756&sort=&pagenum=1&yrstart=1979&yrend=1979 - 79 nautique |
Posted By: Hollywood
Date Posted: May-09-2007 at 1:31pm
If you're getting 4800 rpm what is the problem??? Or is this a typo and supposed to be 3800, else I am very confused.  ------------- |
Posted By: 79nautique
Date Posted: May-09-2007 at 1:35pm
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it goes to 4800 then without moving the throtle backs down to 4200 rpm ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=756&sort=&pagenum=1&yrstart=1979&yrend=1979 - 79 nautique |
Posted By: TRBenj
Date Posted: May-09-2007 at 1:52pm
Chris gets it. If you watch the video, you can see/hear how the boat gets up and goes very well. It gets to about 4800 RPM before it slowly starts to come back down (around the 15 second mark) and finally settles at 4200. Ken stays at WOT in the video up until you see him pull back (just past the 1 min mark). ------------- |
Posted By: Hollywood
Date Posted: May-09-2007 at 1:53pm
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Oh ok. I can't even get anything over 4200, but it will hold there. ------------- |
Posted By: GottaSki
Date Posted: May-09-2007 at 1:56pm
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Uhm, how bout this...
A perferated secondary diaphram could at first actuate, but then may slowly bleed down and close on its own. ------------- "There is nothing, absolutely nothing, half so much worthwhile as messing around with boats...simply messing." River Rat to Mole |
Posted By: Nautique2001
Date Posted: May-09-2007 at 2:03pm
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Sounds like we're going to verify the workings of the check valve by the tank. Advance the timing two degrees. Remove the secondary cover and re-tweek the float. Sounds like a Holley adjustment tool set will help here.
I should have unscrewed the gas cap to see if there's an air restriction. I'll double check the air vent screen. Ken ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=1052&sort=&pagenum=4&yrstart=1986&yrend=1990" rel="nofollow - Nautique 2001 |
Posted By: TRBenj
Date Posted: May-09-2007 at 2:04pm
In that case, would this arm come back down? It stays engaged as long as you stay at WOT, even after the RPM's decrease. 
Ken, it doesnt sound like a float adjustment tool would be helpful. We'll raise it in the rear a bit more, and if that doesnt solve it, we'll raise the front as well and see the effect. ------------- |
Posted By: Nautique2001
Date Posted: May-09-2007 at 2:10pm
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Tim, does the primary have an external adjustment knob or screw? Brad said something about a primary adjustment. Brad's buddy said something about the primary being out of adjustment can effect the workings of the secondary. Can we confirm this?
Ken ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=1052&sort=&pagenum=4&yrstart=1986&yrend=1990" rel="nofollow - Nautique 2001 |
Posted By: TRBenj
Date Posted: May-09-2007 at 2:12pm
Nope, no external adjustment on primaries or secondaries. Chris said that primaries can affect the secondaries as well- so if raising the rear float a bit more doesnt get rid of the problem, we'll raise the front float as well. We'll need a few more tools to get the fuel line off though. ------------- |
Posted By: Nautique2001
Date Posted: May-09-2007 at 2:17pm
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In playing the video back, sounds like we hit 4,800 at 10 seconds and started dropping to 4,200 at 15 seconds. So it takes approximately five seconds for the gas to be sucked out to effect the RPM's. So are we saying the primary bowl is working overtime to keep the secondary bowl filled?
Ken ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=1052&sort=&pagenum=4&yrstart=1986&yrend=1990" rel="nofollow - Nautique 2001 |
Posted By: 79nautique
Date Posted: May-09-2007 at 2:26pm
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1" and 5/8" line wrenches are what's needed for the front, plus a socket to remove the bowl.
Tim I would leave the secondary float alone and raise the front first if the timing doesn't help, set it at 10 not 8 that's where it needs to be anyway. The more timing the better any desent mechanic will tell you the same thing. It's going to be sucking just as much gas out of the primaries as it is the secondaries so if the primary bowl isn't full then there is no way in hell the secondary bowl is going to be full either and raising the float more will not make any change what so ever. ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=756&sort=&pagenum=1&yrstart=1979&yrend=1979 - 79 nautique |
Posted By: Nautique2001
Date Posted: May-09-2007 at 2:32pm
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Excellent input, Chris, thank you. Sounds like you've worked on Holley carburetors before? Are you self-tought or did you take engine courses?
Ken ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=1052&sort=&pagenum=4&yrstart=1986&yrend=1990" rel="nofollow - Nautique 2001 |
Posted By: backfoot100
Date Posted: May-09-2007 at 2:35pm
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This might sound kinda dumb but have you cleaned the screen filter at the inlet of the carb? In fact, I even cut that filter right out of my 4160. You already have the fuel filter to keep the gas clean. That inlet filter is very fine and could be restricting flow even if it's a tiny bit dirty. Just a thought.
Something about the float is not making a lot of sense. Granted the float must be set at the proper height for starters. My concern is something that Chris started to touch on earlier. There is a tube connecting the primary and the secondary bowls in the 4160. If the secondary is emptying faster than it can fill, it will be taking fuel from the primary bowl through that tube wouldn't it? The fuel pump should be filling those bowls more than fast enough to prevent this. That makes me think that the flow into the carb is being restricted (like the inlet filter). It's getting enough fuel to run it at 4800 until the floats drop and then the fuel pump can only keep enough gas in the bowls to run it at 4200. |
Posted By: TRBenj
Date Posted: May-09-2007 at 2:37pm
I may invest in that 5/8" line wrench- I think the only one I have is at the lake. I hear you about the timing, and I agree- but I dont think it has anything to do with this problem. I guess advancing it wont hurt anything though. If you think adjusting the float on the primaries should be the next thing to try, Im all for it. ------------- |
Posted By: TRBenj
Date Posted: May-09-2007 at 2:43pm
Thats not dumb at all- I didnt think of checking that screen. Another good thing to look at. Im with you on the flow restriction. Our initial assumption was that it was a set-up problem since the carb is only a year old, was never water tested by NECC upon installation, and never ran strong from day one. It could very well be something restricting the flow to or from the fuel pump though. ------------- |
Posted By: backfoot100
Date Posted: May-09-2007 at 2:44pm
| Dammmit, Chris, you beat to it with the fron the float adjustment. |
Posted By: Nautique2001
Date Posted: May-09-2007 at 3:12pm
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Sounds logical to work both ends of the carburetor. Just to remind everyone, this carburetor was installed on the rebuild engine July of 2005. It has 23 hours of use on it. I'm comfortable that it's in great shape, but good point on checking the fuel flow through the screen. You never know what the tank will burp up, especially with that corn on the cob fuel mixture.
That little tube that connects the primary to the secondary is clear of turds. I know Tim was looking through it last night. I'm amazed how something minor out of wack can lose 6 MPH. That's about 13% of performance out the window. Ken ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=1052&sort=&pagenum=4&yrstart=1986&yrend=1990" rel="nofollow - Nautique 2001 |
Posted By: Barracuda
Date Posted: May-09-2007 at 3:21pm
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just checking into this thread- I guess I missed some good discussion.
Fact is- was nice to get together with these guys and help one another out. Tim- helluva job last night buddy.We saw some nice results from that secondary adjustment. Thanks everyone for all the tips. This site is a great resource for this very reason. Ken- it's your boat and your call. I'd suggest pulling the fuel filter and screen to see if they're junked up. If not- put em back. If so, replace em. We'll adjust the primary and see if that solves it. While we're at it, we'll bump the timing up a little. As for the oil- I'd recommend draining a quart out of it before you run it. -Brad ------------- Former: http://www.correctcraftfan.com/diaries/details.asp?ID=759" rel="nofollow - '86 Nautique http://www.correctcraftfan.com/diaries/details.asp?ID=507" rel="nofollow - '65 Barracuda |
Posted By: Nautique2001
Date Posted: May-09-2007 at 3:34pm
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Hey Brad,
Thanks for your assistance last night. I'm up for any ideas. The fuel filter isn't difficult to get to, a tad messy though. I have no problem checking the basics before we tear into the primary. I'm going to Auto Zone to pick up some fresh oil and a Mobil 1 filter. I'll start by filling it with 4 quarts, then check the level. Tim refreshed me on the thread about the oil capacity. Man, what a debate that was. Love that video camera. What website did you purchase it on? Ken ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=1052&sort=&pagenum=4&yrstart=1986&yrend=1990" rel="nofollow - Nautique 2001 |
Posted By: 79nautique
Date Posted: May-09-2007 at 3:34pm
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again i really don't think it's a fuel restriction at the tank or one of the filters if it was it would not happen only on the very top end and would start to effect the performance at around 3000 rpm and up.
I say do the timing first beacuse it's not going to hurt to start with and sencondly it's a whole hella lot faster and easier to change than pulling one of the bowls off. ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=756&sort=&pagenum=1&yrstart=1979&yrend=1979 - 79 nautique |
Posted By: Barracuda
Date Posted: May-09-2007 at 3:38pm
Ken- I got it from Adorama.com- they have pretty good prices and are a reputable operation. btw- that was the Sony DCRSR62- so far, I highly recommend it ------------- Former: http://www.correctcraftfan.com/diaries/details.asp?ID=759" rel="nofollow - '86 Nautique http://www.correctcraftfan.com/diaries/details.asp?ID=507" rel="nofollow - '65 Barracuda |
Posted By: 79nautique
Date Posted: May-09-2007 at 3:57pm
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Ok I stand corrected
Called the expert (DAD) and got set straight. (certified ASE Master Technician for over fourty years.) Don't d*ck with the timing or the float, look for a clogged screen at the tank, one of the fuel filters being dirty and needing replaced or the fuel line sucking air somewhere maybe even the early stages of the fuel pump going out. So I guess tighten the hose clamps at the tank and pump, inspect the fuel line for cracks, kinks and replace all the filters or at least that the f/w seperator is thight. ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=756&sort=&pagenum=1&yrstart=1979&yrend=1979 - 79 nautique |
Posted By: Nautique2001
Date Posted: May-09-2007 at 4:11pm
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Vince at SKIDIM suggests getting a reading on the fuel pressure from the pump. Any idea where to get a device to do this???
Ken ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=1052&sort=&pagenum=4&yrstart=1986&yrend=1990" rel="nofollow - Nautique 2001 |
Posted By: 8122pbrainard
Date Posted: May-09-2007 at 4:16pm
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Ken, How about using a pressure gauge Tee'd into the line. ------------- /diaries/details.asp?ID=1622" rel="nofollow - 54 Atom /diaries/details.asp?ID=2179" rel="nofollow - 77 Tique 64 X55 Dunphy Keep it original, Pete < |
Posted By: Nautique2001
Date Posted: May-09-2007 at 4:21pm
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I was just looking at those online. I also found this at NAPA. Is this what I'm looking for? http://www.napaonline.com/MasterPages/NOLMaster.aspx?PageId=470&LineCode=SER&PartNumber=2521&Description=Fuel+Pump+Vacuum+Pressure+Tester - Pressure Tester
Ken ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=1052&sort=&pagenum=4&yrstart=1986&yrend=1990" rel="nofollow - Nautique 2001 |
Posted By: 79nautique
Date Posted: May-09-2007 at 4:22pm
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about any autoparts store will sell a pressure/vaccum gauge for about 10 bucks, It should come with a rubber fitting that you can just slip over the end of the fuel line no need to tee into the line. Just disconnect the fuel line at the carb and push the rubber fitting of the steel line, disconnect the coil wire and crank for thirty seconds and you'll have your ready you need. Ken did you see my other post after I talked to my dad?
------------- http://www.correctcraftfan.com/diaries/details.asp?ID=756&sort=&pagenum=1&yrstart=1979&yrend=1979 - 79 nautique |
Posted By: 79nautique
Date Posted: May-09-2007 at 4:24pm
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ken that's basicly it but it's missing the rubber connecton that slides over the end of the fuel line. ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=756&sort=&pagenum=1&yrstart=1979&yrend=1979 - 79 nautique |
Posted By: Nautique2001
Date Posted: May-09-2007 at 4:28pm
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Yes, Chris, I saw your post. Thanks. I think we have a lot more to inspect prior to removing any more carburetor parts. We'll have a checklist in place, plus I think the fuel pressure gauge is necessary at this point. You said it's missing a piece? Do I need to special order that connection? I'm trying to find an auto store I can drive to versus order on the internet.
Ken ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=1052&sort=&pagenum=4&yrstart=1986&yrend=1990" rel="nofollow - Nautique 2001 |
Posted By: TRBenj
Date Posted: May-09-2007 at 4:38pm
I think thats a good course of action. Verify all your lines, filters and vents are clear and tight between your pump and tank. Then we can move on to the line between the pump and carb, checking the screen as well as the pressure (5 lbs). If that checks out, we'll move back to the float levels, raising the front first. No need to change the timing until we get this all squared away, but we can advance it to about 10 degrees as well. ------------- |
Posted By: 79nautique
Date Posted: May-09-2007 at 4:40pm
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I'll up load a picture of what you need I got mine at autozone I think and it came with the fitting you need to make it quick and easy to check. I would check the other stuff I listed first before worring about the fuel pressure, that would be the last thing to check. I would even change the fuel line from the tank to the pump before checking the fuel pressure anyway odds are it's orginal and needs replaced anyway. ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=756&sort=&pagenum=1&yrstart=1979&yrend=1979 - 79 nautique |
Posted By: TRBenj
Date Posted: May-09-2007 at 4:43pm
Agreed. If we dont find anything obviously wrong with the lines between the pump and tank, it wouldnt be a bad idea to verify the pump is still good. Ken, did you check your receipts to see if the pump was replaced when you had the new engine put in? ------------- |
Posted By: 79nautique
Date Posted: May-09-2007 at 4:43pm
 ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=756&sort=&pagenum=1&yrstart=1979&yrend=1979 - 79 nautique |
Posted By: Nautique2001
Date Posted: May-09-2007 at 4:44pm
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I might have found it:
http://www.autozone.com/selectedZip,01568/initialAction,accessoryProductDetail/initialR,NonAPP23331/shopping/selectZip.htm - Fuel Pressure Gauge . If you confirm that this is the one, I'll buy one tomorrow. We're looking for 5 Lbs of pressure? Ken ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=1052&sort=&pagenum=4&yrstart=1986&yrend=1990" rel="nofollow - Nautique 2001 |
Posted By: Nautique2001
Date Posted: May-09-2007 at 4:45pm
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Hmmmm, didn't post. It's $39 at Auto Zone
Ken ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=1052&sort=&pagenum=4&yrstart=1986&yrend=1990" rel="nofollow - Nautique 2001 |
Posted By: Nautique2001
Date Posted: May-09-2007 at 4:47pm
 ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=1052&sort=&pagenum=4&yrstart=1986&yrend=1990" rel="nofollow - Nautique 2001 |
Posted By: 79nautique
Date Posted: May-09-2007 at 4:47pm
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well the links not woking ken but it should look simular to what I posted big rubber piece with a hose barb on one end ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=756&sort=&pagenum=1&yrstart=1979&yrend=1979 - 79 nautique |
Posted By: 79nautique
Date Posted: May-09-2007 at 4:49pm
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that would be more inline for a FI system where you could screw it into the fuel rail. ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=756&sort=&pagenum=1&yrstart=1979&yrend=1979 - 79 nautique |
Posted By: Hollywood
Date Posted: May-09-2007 at 5:01pm
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Ken slow down with the posts hot damn! You're asking the same questions over and over.
I removed the steel line from the pump to the carb (dangerous i know) and made a new one out of rubber fuel line with a pressure gauge tee-ed in. Total cost was about $30-$40 because of all the brass pieces. This will allow me to run the boat normally while monitoring fuel pressure, for testing purposes only of course. ------------- |
Posted By: 79nautique
Date Posted: May-09-2007 at 5:09pm
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i really doubt it is the fuel pump but might be I would check everything else first, could be just a simple loose hose clamp at the tank since it was just checked out.
kevin all you had to do was cut the steel line and insert a tee with compression fitting and screwed in the gauge at the tee, one fitting, one guage, perminately mounted always know what the pressure is. ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=756&sort=&pagenum=1&yrstart=1979&yrend=1979 - 79 nautique |
Posted By: TRBenj
Date Posted: May-09-2007 at 5:12pm
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I would think a decent parts store (NAPA) would be able to tell you what need to measure the fuel pressure going into a Holley. The fitting is exactly the same as 3/8" brake line, so you can verify the plug right in the store.
Hollywood, have you checked your timing? My '90 was only capable of 41mph @ 4200rpm when I bought it. I never got a chance to put a light on it before the ignition module crapped out, but the new ignition system and proper timing put me at 42mph @ 4400rpm, which is probably about right. ------------- |
Posted By: 79nautique
Date Posted: May-09-2007 at 5:33pm
ken you want an engine vaccum and fuel pressure gauge that looks simular to the picture below. About any auto parts store will have it. If you ask for a fuel pressure gauge your going to get one for a fuel injected motor and you don't want that completely different scale and method to connect it and what you posted earlier.
 ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=756&sort=&pagenum=1&yrstart=1979&yrend=1979 - 79 nautique |
Posted By: 87BFN owner
Date Posted: May-09-2007 at 7:49pm
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Don't forget to check for vaccum leaks. The intake could be leaking once it warms up... Not saying it's your problem, but vaccum leaks are RPM dependent... ------------- |
Posted By: Nautique2001
Date Posted: May-09-2007 at 8:04pm
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Just talked to my Dad. He's got a fuel pressure gauge that measures vacuum and fuel pressure. Good to go.
Ken ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=1052&sort=&pagenum=4&yrstart=1986&yrend=1990" rel="nofollow - Nautique 2001 |