problem solving engine trouble
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=36853
Printed Date: October-07-2024 at 6:28am
Topic: problem solving engine trouble
Posted By: Lift Films
Subject: problem solving engine trouble
Date Posted: July-25-2015 at 2:18pm
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Hey everyone. I have a 76 nautique with a ford 351. The engine was completely rebuilt a couple years ago. After the rebuild, the engine ran great other than one minor problem. When I driving at a slow speed like when I was trying to pull kids skiing the engine would start sputtering and want to shut off. I would have to pump the throttle a few times to keep it running. It ran perfect at higher speeds and I didn't have any trouble accelerating or idling. I thought it was a carburetor problem and tried everything I could think of to adjust it. The carb was also rebuilt/cleaned during the engine rebuild. Also, the carb was a holly Automobile carb so it wasn't even supposed to be on the boat. I thought that may have been the problem anyway. I wasn't sure if they were tuned differently since boats and cars are under different loads. Since that was a safety problem that needed to be fixed anyway I bought a new carb for the boat this year. It is a Quick Fuel M-600. (Here is the thread I started about that: http://www.correctcraftfan.com/forum/forum_posts.asp?TID=36281&KW=&title=where-to-buy-a-holley-carb) The QF carb install was simple. The boat fired right up and ran great in the drive way. I took it to the lake to check everything out and do some final adjustments but I was still having the same problems except this time it was trying to sputter off at slow and cruising speeds. It seemed to be idling pretty high too but I think most of that is because I needed to re-adjust the throttle cable after installing the new carb. Does anyone have any thoughts on what could be causing the engine to want to choke off when cruising? does it sound like a carb tuning issue or could there be something else going on? Thanks for your help! ------------- Luke Pearson |
Replies:
Posted By: Jonny Quest
Date Posted: July-25-2015 at 2:30pm
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Your problem sounds like fuel delivery. If the carb is not getting fuel, even the world's best carb can't do its job. I would look at: 1. Fuel Pump 2. Fuel Filter and/or water separator 3. Fuel tank vent 4. Debris in the fuel tank JQ ------------- Current 2003 Ski Nautique 206 Limited Previous 2001 Ski Nautique Open Bow 1994 Ski Nautique Open Bow Aqua skiing, ergo sum |
Posted By: Lift Films
Date Posted: July-25-2015 at 8:33pm
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thanks, JQ. We cleaned the fuel tank out when we rebuilt the engine so I'm going to mark that one off the list. I also just put a new fuel filter/water separator on a couple months ago. I'm going to do some checking tomorrow to see if the fuel pump is working correctly and go from there. I'll let everyone know the progress. How would you go about checking the fuel tank vent? ------------- Luke Pearson |
Posted By: Jonny Quest
Date Posted: July-25-2015 at 8:57pm
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Fuel tank vent prevents the fuel system from pulling vacuum when fuel is sucked out. The vent can and will plug-up. A good way to check is to remove the gas tank fill cap when running the boat If your fuel delivery symptoms disappear, then you likely have a fuel vent problem. By pulling the fuel fill cap, you are by-passing the vent and directly venting the fuel tank. Simple and easy test. JQ ------------- Current 2003 Ski Nautique 206 Limited Previous 2001 Ski Nautique Open Bow 1994 Ski Nautique Open Bow Aqua skiing, ergo sum |
Posted By: Lift Films
Date Posted: July-27-2015 at 6:07pm
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I'm not able to replicate the problem I'm having when I'm running the engine in the driveway so i'll have to get on the water to do some of these tests. I did just check to make sure the fuel pump was working by unplugging the coil wire, pointing the fuel line from the pump to the carb into a glass jar, and turning the engine over. The pump is shooting blasts of clean fuel directly into the carb so I'm guessing the pump is working correctly. I also don't see any debris in the fuel. I'll try to get the boat on the water as soon as possible to check the fuel tank vent. Any other ideas? Also, my throttle cable is sticky. (When I bump the rpm's up from neutral and then return the throttle to neutral the rpm's don't come back down) Is there a way to loosen up the cable or is it time to replace? Thanks. ------------- Luke Pearson |
Posted By: TRBenj
Date Posted: July-27-2015 at 6:42pm
| Sticky or improperly adjusted? More likely the latter if it's smooth otherwise. |
Posted By: Lift Films
Date Posted: July-27-2015 at 7:14pm
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good question. Before I decided to change the carb it was acting sticky like I said in my last post. After the carb install it was improperly adjusted. When I bumped the throttle forward, the engine would rev up before it went in gear causing the boat to jump. I adjusted the cable exactly like someone mentioned in this thread: http://www.correctcraftfan.com/forum/forum_posts.asp?TID=26601&title=shift-cable-adjustment-pcm-123-and-morse It is working fine now other than when I bump the throttle forward and then bring it back to neutral, the RPM's don't return to idle. ------------- Luke Pearson |
Posted By: Jonny Quest
Date Posted: July-28-2015 at 1:32am
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Not returning to idle could be as simple as a throttle return spring. On the other hand, if the carburetor is over-tightened or improperly tightened onto the intake manifold, the carb body can flex and cause the throttle plates to bind slightly. This could affect return to idle. JQ ------------- Current 2003 Ski Nautique 206 Limited Previous 2001 Ski Nautique Open Bow 1994 Ski Nautique Open Bow Aqua skiing, ergo sum |
Posted By: GottaSki
Date Posted: July-28-2015 at 8:07am
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Also, The quick released on the cable should be adjusted so it provides some light pressure to push against the idle stop every time. ------------- "There is nothing, absolutely nothing, half so much worthwhile as messing around with boats...simply messing." River Rat to Mole |
Posted By: Lift Films
Date Posted: July-31-2015 at 6:28pm
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Gottaski, that may be my problem. I'll check when I get back to the boat. Back to the engine troubleshooting, I've checked all the fuel delivery options and it seems like the carb is getting fuel like it is supposed to. I called quickfuel'd tech line and the guy I spoke with said I needed to go up a jet size. He said the m-600 comes with 67 jets and I need to go up to a 69. I also ran the boat this morning and doubled checked the float levels. They are at the recommended height. I am only getting the hesitation problem around 2000-2500 rpm. If I let the boat cruise at that speed it will stumble. If I don't touch the throttle it will stumble for a few seconds and then resume running normal. After 5-10 seconds it will stumble again and repeat. Any thoughts on any of that? I appreciate yalls help as I learn a lot of this stuff. ------------- Luke Pearson |
Posted By: Jonny Quest
Date Posted: July-31-2015 at 6:39pm
67 jets stock? That is strange. My M-600 came with 65 jets in the Primary and 72 jets in the Secondary. It was my understanding from QF that 65/72 was the base or stock setting for sea-level. Well, as jets are relatively inexpensive, that may be a place to start. The intermittent stumble is a head-scratcher... ------------- Current 2003 Ski Nautique 206 Limited Previous 2001 Ski Nautique Open Bow 1994 Ski Nautique Open Bow Aqua skiing, ergo sum |
Lift Films wrote:Posted By: Lift Films
Date Posted: August-18-2015 at 12:06am
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Still working on this problem. How is everyone's carburetor mounted to the manifold on their boat? My boat is a 76 nautique with ford 351 PCM. My new Quickfuel Carb has two aluminum spacers between it and the manifold. So that makes 3 gaskets. I'm wondering if I may have a vacuum leak and these might be the culprit. The idle problem I mentioned earlier is still there after adjusting everything and I'm pretty sure my throttle cable isn't sticking. I know that a vacuum leak can cause idle problems too. I'm wondering if I need both spacers under the carb. A vacuum leak would explain a lot of the symptoms it's giving me. thoughts? ------------- Luke Pearson |
Posted By: Jonny Quest
Date Posted: August-18-2015 at 1:12am
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2 spacers in series? That doesn't sound kosher. You could always try removing one spacer. How thick/tall is the single spacer? The 2 combined? Be sure to use the marine carb/spacer gaskets. Thicker and stronger. http://www.skidim.com/GASKET-CARBURETOR-SPACER/productinfo/RM0054B/ JQ ------------- Current 2003 Ski Nautique 206 Limited Previous 2001 Ski Nautique Open Bow 1994 Ski Nautique Open Bow Aqua skiing, ergo sum |
Posted By: Lift Films
Date Posted: May-14-2016 at 4:49pm
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Just now getting the boat back out and starting this troubleshooting process again. The boat fired up with no problem today on the hose. Again, I'm not getting the problem on the hose; its only when the boat is under load on the water (approx 2500 rpm). I am still getting the high idle though. It's idling at 1000 rpm. I've adjusted the cable correctly so i'm 99% sure something else is causing the high idle. The first thing I'm checking is for a vacuum leak. I throttled up to 2500 rpm and sprayed soapy water around the base of the spacer plate and carb. I'm not seeing or hearing anything that would indicate a leak. Is there anything I should be doing differently? Or a different place I should be checking? I'm also wondering about the timing. I've seen a few threads talking about how timing could also cause similar symptoms that I'm having. Has anyone found that to be true? I don't have a timing light so I'm going to try to borrow one from a friend to double check the timing. Thanks! ------------- Luke Pearson |
Posted By: tryathlete
Date Posted: May-14-2016 at 7:13pm
| Might be good to have a timing light on to watch the advance under rpm change. It's possible the centrifugal advance is rusty and not moving outward and then snapping out as rpm increases. Lack of timing advance could explain some of your intermittent stumbling. |
Posted By: Lift Films
Date Posted: May-14-2016 at 7:54pm
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thanks. I'll try that. also, does anyone know of what my vacuum readings need to be? Or can point me to resources that shows how to check the vacuum properly? thanks. ------------- Luke Pearson |
Posted By: gun-driver
Date Posted: May-14-2016 at 9:21pm
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To check for a vacuum leak spray starter fluid around the base of the carb. If it is leaking it will increase rpm as it sucks in the starter fluid. Soapy water wont find a suction leak, a pressure leak yes a suction no. |
Posted By: tryathlete
Date Posted: May-14-2016 at 9:41pm
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Posted By: Gary S
Date Posted: May-14-2016 at 9:50pm
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Disconnect the cable from the carb and see if you can get it to idle. Sometimes missadjustment of the cable will cause it to hold open making a high idle. ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=1711&sort=&pagenum=1&yrstart=1966&yrend=1970" rel="nofollow - 69 Mustang HM SS 95 Nautique Super Sport |
Posted By: Lift Films
Date Posted: May-14-2016 at 10:33pm
should I hook up the gauge to the back of the carb or is there a better spot to do that?
Got it. I've read contradicting things about what to spray but I'll give it a shot. thanks for the advice.
good stuff. I wasn't sure if the readings would be different for cars/boats. Thanks for the link. I'll grab a gauge tomorrow and check it out.
I just tested this and it idles high when the cable is disconnected too. ------------- Luke Pearson |
Posted By: SNobsessed
Date Posted: May-14-2016 at 10:44pm
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Vacuum leak could also be at intake manifold gasket to head. Unlikely, but may be worth ruling out. ------------- “Beer is proof that God loves us and wants us to be happy.” Ben Franklin |
Posted By: tryathlete
Date Posted: May-14-2016 at 11:46pm
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Can 'o starting fluid and vacuum gauge should help. That Timing light would still be on my radar. Your going to find this one soon. |
Posted By: Lift Films
Date Posted: May-15-2016 at 6:58pm
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I wasn't able to find a leak with the starter fluid test. Here is my vacuum reading. Also notice the hard start: https://www.youtube.com/watch?v=3zOAW1XTDH0&feature=youtu.be" rel="nofollow - vacuum reading Do you know if my engine is right or left hand rotation? '76 351 PCm My firing order right now is set up as 1 8 4 5 6 2 7 3 Timing is supposed to be set at 10* BTC. I can't even see the numbers unless I rotate the distributor which brings the RPM up above 1000. thoughts about any of this? ------------- Luke Pearson |
Posted By: Jonny Quest
Date Posted: May-15-2016 at 7:29pm
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For a "Normal Rotation" or left hand motor 1-3-7-2-6-5-4-8 is correct. For a "Reverse Rotation" or right hand motor it is 1-8-4-5-6-2-7-3. Sounds like you are reverse rotation. Just to be sure...when sitting in the driver's seat and looking at the engine, if the engine rotates counter-clockwise then you are "Reverse Rotation". If you can't see the timing marks on the harmonic balancer, I would recommend a couple of things: 1. With coil-to-distributor wire unplugged, put a socket on your harmonic balancer and rotate to where you see the timing marks. 2. Clean up the timing marks with a rag and then color the marks in with a white crayon. Then wipe off the excess. This will let you see the timing marks much easier with a timing light. 3. Ensure that you are at Top Dead Center on #1 cylinder. Here is a short https://www.youtube.com/watch?v=RENhHI9n65I" rel="nofollow - video showing you how to find TDC. 4. With the engine at TDC, look at the timing marks on the harmonic balancer. The 0 degree mark should line up with the timing pointer when the engine is at TDC. This will give you a reference starting point. If your timing marks are not visible, double check that you are at TDC on cylinder number one (1) compression stroke and not 180 degrees off on the exhaust stroke. If you still can't see the timing marks, you may need to buy some timing tape like http://www.summitracing.com/parts/sum-163594" rel="nofollow - this . Then you can re-set the timing. JQ ------------- Current 2003 Ski Nautique 206 Limited Previous 2001 Ski Nautique Open Bow 1994 Ski Nautique Open Bow Aqua skiing, ergo sum |
Posted By: Lift Films
Date Posted: May-15-2016 at 9:04pm
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Ok timing is adjusted properly so I can mark that off the list. I'm still getting a high idle (approx. 1000 rpm). Can a bad PCV valve cause a high idle? Should it be air tight? It's loose enough I can wiggle it around and pull it right out with almost no friction. I've tried unhooking the throttle cable and loosening the idle screw on the carb. Neither will bring the idle below 1000 rpm. ------------- Luke Pearson |
Posted By: Bri892001
Date Posted: May-15-2016 at 9:30pm
| Hmmm, maybe the rubber gasket in the valve cover for the PCV valve is missing or totally worn out. This is a rare situation, but maybe a the PCV to valve cover gasket got lost during the rebuild. It's not normally super tight, but there should be some friction. Maybe there's the vacuum leak right there? |
Posted By: SNobsessed
Date Posted: May-15-2016 at 9:31pm
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Plug the PVC entirely, for a test. Then you will know if it is the cause. ------------- “Beer is proof that God loves us and wants us to be happy.” Ben Franklin |
Posted By: Lift Films
Date Posted: May-15-2016 at 10:27pm
The rubber gasket/grommet is there but it must be worn out because the PCV valve is definitely loose. It's looser than I feel like it should be anyway. Those parts are so cheap I may just order them anyway.
Might be a dumb question but should I plug both the port going into the carb spacer as well as the hole where the PCV valve sits? ------------- Luke Pearson |
Posted By: tryathlete
Date Posted: May-15-2016 at 10:31pm
| Both |
Posted By: gun-driver
Date Posted: May-16-2016 at 12:21am
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Have you adjusted your idle mixture screws at all??? https://www.youtube.com/watch?v=UPGLUsW5ZeE" rel="nofollow - https://www.youtube.com/watch?v=UPGLUsW5ZeE |
Posted By: Bri892001
Date Posted: May-16-2016 at 12:59am
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I started poking around a little bit. I guess there are different sizes and vacuum ratings for pcv valves, which makes sense. Something I honestly gave hardly any thought to. You might have one with too small a diameter. You're right that's it's a when-in-doubt-replace-it sort of part. |
Posted By: Lift Films
Date Posted: May-16-2016 at 11:46am
any idea how to figure out which PCV valve/grommet I need for my engine? I've been digging around all morning and can't find anything that says exactly what I need. I found this pcv at skidim... http://www.skidim.com/VALVE-PCV-90-DEGREE/productinfo/R035015/ ...but haven't been able to find an exact replacement grommet. I would love to find an automotive equivalent that I can pick up in town so I can check it out today. ------------- Luke Pearson |
Posted By: Bri892001
Date Posted: May-19-2016 at 11:10pm
| Any luck? I'd imagine the grommet would be kind of standard for all 351s? |
Posted By: Lift Films
Date Posted: May-19-2016 at 11:29pm
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A new PCV valve and hose arrived today. The grommet appeared to be fine so I'm leaving it in. I'll get these in tomorrow and give it a try. I'll report back once I know something. ------------- Luke Pearson |
Posted By: Lift Films
Date Posted: July-29-2016 at 8:18pm
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okay, here is where I'm at now: PCV Valve didn't fix the problem although the old one was definitely worn out and not functioning properly. Timing is now set correctly (according to manual). I've been at the lake with the boat twice this week to think through possible scenarios. Here is what's happening: -The boat is now idling fine. -The boat starts quickly and accelerates quickly. It takes fuel fine. I can throw the throttle down and it will take fuel and accelerate without a hitch. -It runs fine below 2000 RPM and above 3000 RPM. -When I bring the boat to approx. 2500 RPM and let it cruise at that speed, it takes about a minute before it starts to stumble. -The stumble sounds like its too lean or too rich ( I can't tell). -The stumble last for about 2 seconds before it catches back up and resumes speed. -3 seconds later the stumble happens again. -This stumble pattern just continues as long as you keep the boat under load between 2000-3000 rpm. (Its the worst around 2500). Every 3 seconds like clockwork. -If you accelerate really quickly and run the boat hard for a few seconds and then bring it back down to 2500 rpm, then it takes about a minute before the stumble starts again. Any other ideas based on that? Could float levels cause these symptoms? I have new gaskets from Skidimi and new jets for the carb (a size up and a size down). I plan on trying the jets first. If that doesn't work then I'll take the carb off, clean the surfaces, and use the new gaskets to hopefully fix any vacuum leaks (although I haven't been able to find any). Thanks for following this thread and helping me troubleshoot. ------------- Luke Pearson |
Posted By: SNobsessed
Date Posted: July-29-2016 at 9:21pm
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You could watch the secondaries' linkage when it is acting up. Maybe there is something wrong with the secondaries vacuum diaphram, like a pinhole. ------------- “Beer is proof that God loves us and wants us to be happy.” Ben Franklin |
Posted By: Chris74
Date Posted: July-29-2016 at 10:38pm
| Sounds like a lot of the same problems I'm having.the information I found on vacume said it suhould read around 16 |
Posted By: Chris74
Date Posted: July-29-2016 at 10:40pm
| What did your manual tell you to set timing to ? |
Posted By: MrMcD
Date Posted: July-29-2016 at 11:18pm
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Have you verified the timing is advancing smoothly from idle all the way up and not jumping and sticking as you increase RPM. Easy check, install a timing light and watch the timing marks as you rev the engine. Should be identical each and every time and very smooth as the timing moves from your idle setting to max centrifugal advance. Common problem in boats is rust on the distributor advance weights making them sticky. I have seen this problem twice in friends boats. |
Posted By: MrMcD
Date Posted: July-30-2016 at 5:05am
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I see you set the timing and I guess you did this at idle which is normal. Engine performance is very much controlled by the Mechanical advance in your distributor. It normally functions perfectly and is invisible. When they act up you need to verify what they are doing to fix them or verify it is working perfect and move on to other potential problems. The simple check would be to hook up the timing light to your number one spark plug. If you question what plug is number one, look down on the front of your engine above your fan belts. As you look down notice that one cylinder head is actually about 1 inch forward of the other cylinder head. The forward head and the front cylinder is where your number 1 plug will be located, Chevy, Ford Chrysler all the same., With the engine running and timing light working have a partner rev the engine up slowly from idle 650 RPM to 4,000 RPM watch the timing mark on your harmonic balancer move. It should move from the factory setting of 5 degrees or so at idle all the way up to 35 degrees by 3,000 RPM. If it is sticky, jumpy or does not move this is a major issue and needs fixed. Fix is simple, take the cap off the distributor remove the points and condenser and get down to your advance weights under the points. Make sure they are clean, no rust. The springs are still attached. Turn the shaft gently and watch the springs move and the weights swing. Make sure the weights are clean and smooth. If you take them out a quick smoothing with 600 grit sand paper will make them work well again. I always coat them with a very thin film of marine grease. I understand many say to keep them bone dry. I use the thin coating, just a film, to help avoid future rust. I know the coating can attract dirt and dust. Choose your poison, dirt or rust both can mess it up. Timing should advance as RPM goes up. If you are 5 at idle it might be 15 at 1,500 RPM and 20 at 2,000-2,500 and max at 35 + or - 1 at 3,000-3,500. Keep checking all the way to 4,000 so you are positive where it stops advancing. As was mentioned many posts back on this thread timing could cause your issues if it is not advancing correctly as your RPM go up. |
Posted By: Lift Films
Date Posted: July-30-2016 at 10:26am
10 BTDC ------------- Luke Pearson |
Posted By: Lift Films
Date Posted: July-30-2016 at 10:42am
Good idea. We thought the same thing and watched these good. No sign of leakage from secondaries.. ------------- Luke Pearson |
Posted By: Chris74
Date Posted: July-30-2016 at 10:48am
| I have checked for advance it is good and smooth.get up just over 30 at 3500 rpm.My timing marks only go up to 30.The distributer seems to be fine.i honestly think my whole problem has been timing.will verify this week end though .The confusing thing is wether it should actually be 5 or 10 degrees..From what I can tell now I believe my motor be a WRD motor actually refers to RD setting which say the timing should be at 10 degrees not 5 which I have been setting it to for years. |
Posted By: Lift Films
Date Posted: July-30-2016 at 10:52am
thanks. I'll double check this today. Pretty sure timing is advancing correctly though. I'm not getting any pings or backfires. Boat accelerates fine and runs great at high RPMs. Also not sure why it would run fine for a minute before the stumbling starts if it was a timing issue. It is literally like clock work. It'll run perfect at 2500 RPM for 1 minute and then start stumbling every 3 seconds until you accelerate. When you bring it back down to 2500 rpm it will take another minute to start stumbling. and maybe stumbling is the wrong word. It sounds like a bog; as if it's getting too much fuel or starving for fuel. ------------- Luke Pearson |
Posted By: MrMcD
Date Posted: July-30-2016 at 2:51pm
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Run the timing your engine calls for, it is not the same in all engines. That is why some say 5 and some say 10 degrees. Run what your engine calls for as a base. If your timing advances smoothly every time and does go up over 30 as you state it, you ruled out timing as a possible cause. Check it off. If it is sticking at any point it can cause big headaches and boat distributors do rust and eventually stick. or the springs rust out and fail making your advance curve bad. For your engine to perform timing has to advance smooth and linear, each time the RPM changes. My carb knowledge is weak so I will let the experienced help you on that. I would think if you can run it wide open for a minute and not starve for fuel you don't have a supply issue or a float issue. A leaking diaphragm on the secondarys would leave them closed at all times and cost you power but not make it run erratically. From what you describe it sounds like the secondarys in your 4 barrel are working fine and the primary system is where your issue is. When you water test it have help to drive for you. With the engine cover up manually open the secondarys and see if your problem happens at 2,500 running on the secondary with the primary still set at idle. Might give you a clue where to focus. |
Posted By: KENO
Date Posted: July-30-2016 at 3:35pm
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Hi LiftFilms Having read thru all of this thread and all of last year's, I don't see any mention of what kind of distributor you have. Lots of talk about timing and advance mechanisms, nothing about points or electronic. I've seen both do some strange things.that are hard to explain. Will the boat run at say 3000 or 3500 rpm's for a minute or more with no issues? If I put on a brand new carb and that didn't resolve my issues I'd be looking elsewhere and I can't count how many times over the years I've been sure something was a fuel issue only to figure out it was ignition instead KenO |
Posted By: Lift Films
Date Posted: July-30-2016 at 4:18pm
It is a prestolite sae-j1171 Once you get to 3500 rpm the problem goes away completely. at 3000 rpm it is there but almost unnoticeable. at 2500 it is the worst. below 1800 it is non-existent. ------------- Luke Pearson |
Posted By: KENO
Date Posted: July-30-2016 at 4:36pm
The SAE j1171 just m eans it's a marine distributor. That was the SAE testing that qualified it as marine. But at least you know it's a marine Prestolite If it's points and you haven't touched them in a while, I'd do points, rotor, cap and condenser and a coil while I was at it. Just a stock replacement type coil Can't hurt that's for sure. Electronic might have it's own set of problems that would be a little harder. KenO. |
Posted By: Lift Films
Date Posted: July-30-2016 at 10:13pm
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Update: I went out to the lake today and tried switching out the jets so I could mark another thing off the list. The carb came with 67 jets from the factory. I tried 65 jets and didn't notice much of a difference. I then tried the 69 jets and the boat ran noticeably worse. It idled worse, had less power, bogged, etc. I'll switch it back to factory size and mark the jets off the list. I didn't have anyone with me where I could check timing advance. I'll try that tomorrow or monday. ------------- Luke Pearson |
Posted By: TRBenj
Date Posted: July-30-2016 at 11:25pm
| Listen to KENO. I'd continue to troubleshoot the ignition... Doesn't sound like carb. I've seen EI modules misbehave at specific rpm and act fine above/below. |
Posted By: Lift Films
Date Posted: July-30-2016 at 11:58pm
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I'm moving to ignition now. My boat has standard ignition with points. I'll start checking each of KENO's suggestions off the list. thanks for the help. ------------- Luke Pearson |
Posted By: KENO
Date Posted: July-31-2016 at 10:01am
If you want some part numbers, here goes. These are for the Prestolite clip down cap which is what came on the 76's. If you have the later screw down cap the cap and rotor are different These are all Standard Motor Products but could be cross referenced to another brand Points AL-5677P Condenser AL-118 Rotor AL-153 Cap AL-140 (cheap one) or AL-483 (expensive one, brass contacts instead of aluminum) Coil UF-2 Ballast resistor RU-4 (RU-23 or RU-37 will work too) Or you can go to discount Inboard Marine's website and get a 1301 tuneup kit (cap, rotor, points and condenser) and 1243 ballast resistor and 1223 coil. May or may not cure your problem, but you'll know your ignition system is right. KenO |
Posted By: Lift Films
Date Posted: July-31-2016 at 1:13pm
My cap is the screw down version. So the cap and rotor are the only things that are different? Which brings up another point. What is the best way to tell what year model a nautique is? The papers for my boat show two different numbers. Previous owners didn't keep up the documents very well so there was a lot of confusion when I purchased it. I really want to know the source of the problem so my plan is to change components one at a time until the problem goes away. ------------- Luke Pearson |
Posted By: MrMcD
Date Posted: July-31-2016 at 1:47pm
| My 78 had a serial number in the back drivers side right below the rub rail and the year of build was in that number. |
Posted By: KENO
Date Posted: July-31-2016 at 2:36pm
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If it's a screw down cap then you would use a 1302 kit from Discount Inboard Marine instead of the 1301. I don't have any Standard brand numbers written down for the cap and rotor for the screwdown cap. |
Posted By: Lift Films
Date Posted: August-02-2016 at 10:19pm
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KENO, Just getting back on this. I just double checked and my distributor has the electronic conversion. It has the screw down cap with a Mallory 6100M Distributor Module. What do you recommend doing on that? ------------- Luke Pearson |
Posted By: KENO
Date Posted: August-03-2016 at 12:22am
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Hi Lift Films Bet you were surprised when you popped the cap. I think about all you could do short of replacing the e spark unit would be to clean the rotor and cap contacts if there is any corrosion etc on them. That would be by scraping the stuff. off. You could clean the photo optic eye with some spray electrical contact cleaner. Don't use brake parts cleaner. We won't get into why I say that If I suggest getting a new e spark kit, it'll probably turn out to be wrong and not cure your issue, then again if you don't get one you won't know. Kinda a Catch 22 situation. Like TRBenj mentioned earlier the electronics can do strange things, but I'd start by making sure things are clean like I mentioned above One other thing, look at the Mallory instructions and make sure it's wired the way they tell you to. Much of this depends on what you're using for a coil. KenO |
Posted By: Lift Films
Date Posted: August-03-2016 at 4:18pm
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Thanks KENO. Should the coil be the same as the one you mentioned earlier? UF-2? ------------- Luke Pearson |
Posted By: fanofccfan
Date Posted: August-03-2016 at 5:11pm
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For what it is worth. I took a screen shot of KENO's above post with the part numbers. Took it to the parts store ordered them all and was up and running in no time! Thanks KENO, |
Posted By: KENO
Date Posted: August-03-2016 at 6:18pm
The coil I've been using with an e spark is a Mallory 29219 http://documents.msdperformance.com/61004m.pdf" rel="nofollow - mallory instructions The linked instructions talk about coils and ballast resistors right at the beginning, the 29219 is one of the 3 listed for use without a ballast resistor. I went that route and haven't had any problems The instructions can be confusing, these particular ones are for an e spark in a Mallory distributor but the wiring is the same for all the e spark kits. |
Posted By: Lift Films
Date Posted: August-03-2016 at 7:57pm
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Ok. I have a new coil ordered. I'll get the rotor and cap cleaned up and double check the wiring once the coil comes in. Hopefully my problem is with the coil. How do you know what coil will work with the e spark? The coil currently on the boat is a C819 (autozone). ------------- Luke Pearson |
Posted By: KENO
Date Posted: August-03-2016 at 11:04pm
That Duralast c819 coil is 1.5 ohms according to auto zone. You would wire your e spark per figure 5 of the instructions I attached at the bottom of page 2 of this thread. You would have a ballast resistor as part of this wiring. The mallory 29219 coil gets wired with no ballast resistor. The odd part is that it's also about the same resistance. It's 1.4 ohms. So the 64,000 dollar question is why the Mallory coils that they specify in the instructions (the 29219 is one of them) don't need a ballast resistor. I don't know the answer but that's the coil I've been using for quite a while with no issues. Must have to do with the coils internal construction. The 29217 is wired per figure 7 |
Posted By: Lift Films
Date Posted: August-05-2016 at 6:08pm
What type of rotor and shutter do you have with the e spark? I've cleaned up the old rotor and was ready to install it but wanted to make sure this setup was even correct.   ------------- Luke Pearson |
Posted By: KENO
Date Posted: August-05-2016 at 8:26pm
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That's what an E spark for the screw down cap should look like. If you want to get at the photo electric eye you have to pull the shutter/rotor assembly off, sometimes they can be stubborn KenO |
Posted By: Lift Films
Date Posted: August-16-2016 at 4:30pm
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I spent a full day on the lake Saturday with two guys that know a lot more about engines than I do. Here is what we found out. 1) All the spark plugs were black and we found one that wasn't firing. We went ahead and changed them all out. 2) We double checked the timing advance and it seemed to be advancing fine. The weights and springs move freely and we reved the engine up to make sure it wasn't getting hung up anywhere. 3) We played with different timing settings and actually found that the main problem we've been having (stuttering under load) completely went away when we changed the timing to top dead center (or set at 0 degrees). The only problem with that is we were not getting as much power out of the gate with that setting. It was noticeably sluggish to get up on plane. When we brought the timing back to 10 BTDC it had plenty of power but the problem returned. 4) We put a new coil and distributor cap on which didn't change anything. 5) We checked for vacuum leaks again by spraying around the carb but there were none that we could find. We removed the carburetor and changed both gaskets to thicker gasket material just to be safe. Everything was flat and clean and there were no signs of a vacuum leak. 6) While we had the carb off we decided to change the jets back down to a smaller jet size since we knew we were running rich anyway. The carb came with 67 jets so we went down to 65 jets. After we did this we found that we could get the timing set to around 6 BTDC without having the problem occur and very little power loss out of the gate. a definite improvement. 7) So we left the lake on saturday with the boat running pretty well overall but the timing is set to around 6 BTDC. I ordered 63 jets so I could try that size to see if we could get the timing set to 10 BTDC without losing power or having that stutter under load. looks like we've finally made some progress. Any other thoughts based on this info? ------------- Luke Pearson |
Posted By: SNobsessed
Date Posted: August-16-2016 at 5:26pm
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You may want to check your timing chain for wear. See other thread, just move crank with a wrench & see if dizzy moves immediately. ------------- “Beer is proof that God loves us and wants us to be happy.” Ben Franklin |
Posted By: MrMcD
Date Posted: August-16-2016 at 5:27pm
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Glad you are making progress. If you have black plugs it is rich, does not sound like a vacuum leak. You are on the right track. It does sound like your distributor advance springs may be letting the advance come in too soon. Are stiffer springs available for this distributor? |