Stuck at 2500 RPM- 87 Martinique 454
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=3677
Printed Date: November-23-2024 at 12:47pm
Topic: Stuck at 2500 RPM- 87 Martinique 454
Posted By: boyn0010
Subject: Stuck at 2500 RPM- 87 Martinique 454
Date Posted: May-25-2006 at 11:10pm
| I purchased a 1987 Martinique with a rebuilt 454 about a month ago and have yet to get it going right. At first, the marina told us there was a small carb problem, but because it was not running right, I got a great deal on it. The boat had been sitting for two years so we figured a quick carb rebuilt, fresh gas and plugs and I would be on my way. Since I brought it home, I have replaced the distributor (the PCM recommended Mallory), coil, plugs, wires, thermostat, impeller, fuel filter, and carburetor. At first, we thought it was just a timing issue since the centrifugal advance in the Prestolite did not advance. After we straightened that out, we purchased a Holley 4160 650 cfm through SKIDIM. This is the PCM factory replacement carb. Once we put that on, I had it running great for a couple hours then the engine began flooding. Gas would drip into the primaries even with the boat off, so we had a new carb sent out and same problem. We have messed with the timing and the carb but still cannot get about 2500 RPMs while in gear. In neutral, the engine will rev up without a problem. I have talked to so many people about this boat (SKIDIM, Correct Craft, PCM, other PCM dealers) and am running out of ideas. According to the rebuilder, a new cam was not put in, but they replaced the valves, pistions (and bored them out), lifters, and intake (an Edelbrock performance intake). The rebuilder as well as the owner who traded it into the marina both mentioned there had been a carburetor problem but both figured a rebuild would solve it. The carb was so bad it could not even be rebuilt, but even with a new one, still no luck. At this point, having two new carbs and the same problem, I think I can safely rule out that the carb itself is the problem. Possibily the carb will not match up with the intake (I have the metal plate that SKIDIM recommends) or the engine somehow. Any help would be greatly appreciated. Thanks. Scott |
Replies:
Posted By: Munday
Date Posted: May-26-2006 at 12:17am
|
It did run great on the water?
If it did that rules internals out like cam timing. If fuel is leaking out of carb then floats must be to high,or have debris in needle and seat.Do you have rubber fuel line after the fuel filter?Sometimes they start coming apart inside, sending crap to carb. Good luck Munday |
Posted By: boyn0010
Date Posted: May-26-2006 at 8:48am
|
Yes, I had it up to full speed and 4400 RPMs. When you went from zero to full speed, it had a slight pause, but I hear that is how all carbureted engines are. So basically, it ran great.
We actually checked the mechanical timing and the cam and crankshaft marks do line up, so that has been ruled out. The carb I put on is brand new and replaced a brand new one and they are both from PCM and PCM and SKIDIM both tell me that they come calibrated for my engine. I do have a rubber fuel line after the remote filter. I took that off to inspect it when I changed the filter and it appears fine. The fuel line between the pump and carb has been replaced and I have added a fuel regulator (I was getting abotu 7 psi of pressure and now have it between 5-6 where it is suppose to be) and an in line fuel filter. Thanks for the response. Scott |
Posted By: 79nautique
Date Posted: May-26-2006 at 9:14am
|
THE CARB IS NOT ADJUSTED CORRECTLY
It is foolish that so many people on this site believe that you can just get a new carb and not have to adjust anything and it is the correct model and is calibrated for this application is a bunch of bullsh*t. All that say's it that it is the correct CFM carb and is jetted for that application, it does not mean that the float is correct, it does not mean the accelartor pump is set correctly, it does not mean the choke is set correctly, it does not mean the idle mixture screw are set correctly. your statement that the engine had a slight pause and that is nornmal for a carburated engine is bullsh*t too and a clear indication that the carb is not adjusted correctly. I question the skill of the people giving you advice and who rebuilt your engine. I've never seen or heard of a quilty engine builder that reuses the cam on a rebuild. If the bearings are shot on the crank then they are shot on the cam as will and the lobes are flatted as well and the cam needs replaced, why send good money on a rebuild and use worn out parts. By using the old parts and not replacing with new parts shortens the life of the engiine dramaticly and something that only an amature would do or a tight wade that is too cheap to do it right. ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=756&sort=&pagenum=1&yrstart=1979&yrend=1979 - 79 nautique |
Posted By: boyn0010
Date Posted: May-26-2006 at 9:56am
|
I have been talking with Holley, Vince at SKIDIM, Max at PCM, and Bruce at Midwest Correct Craft. They are all telling me that aside from the idle mixture screws and main idle adjustment screw, I should not have to make any other adjustments. I considered some other adjustments you mentioned after reading the manual but not sure what really to do.
The engine had been rebuilt before I bought it. He told me the cam was in great shape and he could not find a performance one (he is a car guy and the engine is reverse/right hand rotation) that would be better. The story I got from the previous owner (he had already traded it in the marina so had no real reason to lie) and the rebuilder is that the engine had not hatched, but instead the owner just wanted to supe it up. I know that does not make sense, especailly since he paid all that money and did not get a new cam, but that is what I have been told. I just got off the phone with Vince and I am going to recheck the plug wire sequence (for the 100th time), make sure my dampener's top dead center mark is actually top dead center, and do a compression check. Any thoughts? |
Posted By: martini
Date Posted: May-26-2006 at 12:42pm
| I agree with 79, adjusting/setting up the carb is an absolute necessity and they never run correctly straight from the box. Case in point, I purchased a new Holley carb for my 351W and had a lean surge due to an incorrect power valve for my application. It was sent with a 2.5 and I needed a 6.5 to make it run right. That was the main problem, but I still needed to make sure floats were correct and I absolutely had to adjust the idle mixture screws, idle screw, accel. pump, linkage and choke. |
Posted By: boyn0010
Date Posted: May-26-2006 at 1:14pm
| I am going home to do some testing now. I will re-post after I find out more. |
Posted By: 79nautique
Date Posted: May-26-2006 at 10:22pm
|
Scot where are you located?
I wasn't trying to be an ass but I usually come accross that way, but if you suppect a carb issue swaping carbs most of the time isn't going to fix things. And if the cam was fairly new then using it on the re-build wouldn't be an issue but if it had a lot of hours on it then maybe it wouldn't be the best thing to do. If you knew the PO for a while then that's to your advantage or carries more wieght, but if they are unknow or new to you, then odds are it's a song and dance trying to smooth things over. Since it ran pretty good at first and you got 4400 rpm look for water in the fuel, a satureated filter, even if it was new, it could have soacked up water and needs to be replaced again. look for collapsed fuel lines, check for vaccum leaks, look for something simple, loose coil wire, spark plug wires, choke wires blown fuse to the choke. don't assume it is the carb. start simple then go to the more complicated stuff. ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=756&sort=&pagenum=1&yrstart=1979&yrend=1979 - 79 nautique |
Posted By: stang72
Date Posted: May-27-2006 at 2:17am
|
I totally agree with the "new" carb does not mean it's bolt on and go...Every new holly I have purchased needed some adjusting.
If it it's dripping fuel, I would check the level of the floats first...also if it is cutting out at about 2500 rpms, the secondary bowl level may need to come up. You should have a screw on the side of each bowl... on the primary bowl(toward the bow)remove the screw and see if fuel runs out...it should be right at the bottom of the screw hole and not running out...check the secondary bowl too. Keep in mind the other adustments that others have mentioned are all part of the correct set up. Good luck! ------------- stang Face plants are not that funny when it's you face! http://www.correctcraftfan.com/diaries/images/3720/photo1.jpg" rel="nofollow - The Super Air |
Posted By: GottaSki
Date Posted: May-27-2006 at 7:08am
I concur, beware. When done right, a carb engine runs as good as efi, minus that Fran Dresher whine the fuel pump makes. ------------- "There is nothing, absolutely nothing, half so much worthwhile as messing around with boats...simply messing." River Rat to Mole |
79nautique wrote:Posted By: boyn0010
Date Posted: May-27-2006 at 10:08am
|
First, 79nautique, I am on Lake Minnetonka in Minnesota (about 15 minutes west of Minneapolis).
Second, I fixed the problem and am embarassed to admit what the problem was because it something we have battled a couple of times. The plug wires for 6 and 8 were swapped. This happened when a friend of mine helped me pull the plugs out after it flooded last weekend. I definitely would have checked this sooner, but I was under the impression that the engine would backfire and not start if the plug wire sequence was wrong. Well I know that is not true and will never let this happen again. It is now running pretty well. I still have a couple questions. 1. So 79nautique and GottaSki, are you telling me I should be able to go from dead idle to full throttle and it should just jump out of the water? It does not really dog on me but if I just hit it, it just does not pop out the water as fast as I thought it would. This is my first Correct Craft but I have driven other inboards. I figured with the 454, this should fly out of the water when you hit it. 2. It is still starting hard and I am not sure if it is flooding (I do not smell gas and it runs fine once it is going). The leaking carb problem has stopped (I am assuming that was related to the plug wire problem). I am thinking about adjusting the thermostatic choke and resetting my idle mix adjustment screws back to 1.5 (currently at 2.5). Any thoughts? Thank you to all who have responded. This is a great forum. |
Posted By: GottaSki
Date Posted: May-27-2006 at 10:31am
|
Remember you likely have a 14" prop not a 13, and the 330 engine has a little more oomph and grunt but remember there is a couple hundred extra pounds of cast iron you toting. Now if you had the 425 engine....you wouldn't have asked.
To be EFI smooth everything has to be spot- on..aggressive initial advance, good curve, optimal final with no pinging. Thats where mallory distributors shine because its easy to set the span on the advance, but the advance mechanism is prone to wearing out nylon bushings and getting sloppy, so check that. Carb accel pump adjusted with no slop, no vacuum leaks, air screws set right on, not 1.5, 2.5 out, not highest vacuum sitting still, but strongest, smoothest idle in gear. Primary Power valve typically 6.5 to 8.5. New carbs seem to ship with a 2.5 and most find a 2.5 is too late to richen up causing a lean dull spot when dumping the throttle and the accel pump stops squirting. Main jets sized to get a 1.5-2mm soot ring on the base of the plug insulator...(you have to cut away the threads to see). The mains should be pretty close but if you disable the secondaries and take it for a WOT rip then you can read the plugs and know whats going on with the primaries. If its dark or tan its too rich..white insulator is what you are after, but after that you must look at soot ring width. Grey plugs are bad, too lean, very bad. When the primaries are optimized reactivate the secondaries and repeat the WOT plug chops and set the secondary jets or metering plate. Most can get it quite close without changing main jets, but it doesn't hurt to check for sanity. ------------- "There is nothing, absolutely nothing, half so much worthwhile as messing around with boats...simply messing." River Rat to Mole |
Posted By: boyn0010
Date Posted: May-27-2006 at 11:00am
|
GottaSki, I had a 13" x 16P 4 blade on there which I swapped out for a factory recommended 13" x 12.5P because I could not get my RPMs up to 4400 and it would move to fast at idle. Speaking of the 425HP, have you or anyone else ever seen one of those in a Martinique? That is what I wanted but could not find one anywhere.
The Mallory distributor I have is brand new so I doubt anything is worn or broken. Is there another adjustment I should make on the distributor other than adjusting my initial timing? How do I know what size primary power valve I have? This carb should be setup the exact same as the original carb that came with the boat, according to PCM and SKIDIM, and the manual says 85 for the Power Valve. What does WOT stand for (wide open ___?). I am not sure about cutting away the threads. I am also not sure what the plug insulater is. Do I disable to secondaries by having someone manually restrict them? Thanks again. |
Posted By: GottaSki
Date Posted: May-27-2006 at 12:33pm
|
12.5 pitch on a 1:1 boat with a big-block sounds like not enough prop unless you got the thing overloaded with fatasses and water ballast for boarding. Then again, the Martin is heavier.
What rpm does it hit now with the 12.5?? I question the advice you got. It would be in your interest to get a 14 so to bring the cruise rpms down a bit and not have to use so much gas, IF you spend a lot of time over 30 mph. It sounds like I got too advanced for your current proficiency. Start with the easy stuff. First, Focus on optimizing the timing, air screws and accel pump, find a 14p prop. If it still doesn't launch hard, get some gaskets and openup the carb bowl and metering block to get the main jet numbers and PV number, have a 8.5 in hand to install then reassemble and retune. don't worry about reading plugs till you cover the basics, then you can be pointed to well-written methods to check and tune the mains. Walk before you run. ------------- "There is nothing, absolutely nothing, half so much worthwhile as messing around with boats...simply messing." River Rat to Mole |
Posted By: stang72
Date Posted: May-27-2006 at 3:16pm
|
WOT...Wide open throttle!
Your prop should be good for hole shot with 12.5 pitch...the lower the pitch = quicker out of the hole...higher pitch better top end speed. As far as what to expect for hole shot...if pulling a slalom skier(ave wieght) out of the water...your boat should almost yank his arms off if you hit it wide open. So...it should pretty much jump up and get on plane fast! ------------- stang Face plants are not that funny when it's you face! http://www.correctcraftfan.com/diaries/images/3720/photo1.jpg" rel="nofollow - The Super Air |
Posted By: boyn0010
Date Posted: May-28-2006 at 10:58am
|
GottaSki, Correct Craft technical support and SKIDIM both had the 13 x 12.5 listed as the factory recommended upgrade (from the 3 blade standard prop) for my boat. I am getting right around 4400 RPMs like I should.
I am going to pull my first skier today and will repost later tonight. I think my biggest issue is I have nothing to compare this boat to. I have never owned a Correct Craft or other inboard ski boat. I have driven a Mastercraft but that was a couple summers ago. My expectations are obviously set pretty high given the size of the engine. I will say, it does throw the people in the boat back when I hit the throttle if they are not hanging on and it planes out within a few seconds pulling a tuber (did that yesterday). I think I will need to get side by side with another Correct Craft to judge my performance. |
Posted By: Martinique87
Date Posted: May-28-2006 at 1:55pm
|
Scott,
Where do you live? If your around Central Florida I have an 87 Martinique with a 351. Be happy to meet up and do a side by side. I'm sure yours will wlak mine outof the hole, but you'd get a good comparison. I also have an 89 SN with the 1.23:1PCM tranny. Much better whole shot than my Martinique. I like driving the SN better but the family still likes the Martinique the best. Tim |
Posted By: Martinique87
Date Posted: May-28-2006 at 5:23pm
|
Scott,
Just read that you are in Minnesota. That would be a heck of a commute for you, but the offer still stands 
Tim |
Posted By: boyn0010
Date Posted: May-29-2006 at 8:17pm
|
Tim:
Thanks for the offer. I can hopefully find someone around here to do hole shot test against. Thanks. Scott |
Posted By: Nautique2001
Date Posted: May-30-2006 at 9:57am
|
Scott,
Glad to see you're up and running! You should be ship shape for years to come. Enjoy! Ken ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=1052&sort=&pagenum=4&yrstart=1986&yrend=1990" rel="nofollow - Nautique 2001 |
Posted By: HAmick
Date Posted: May-30-2006 at 10:24am
| I am no expert but I do know SEVERAL top car guys adjusted my carb and it was just OK.... I found as ex PCM mach., he spent about 20 minutes in it and it ran better than the day I got it. That was 7 years ago. After sitting up for 5 years it started the second time I turned the key. |