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KENO 
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Joined: June-06-2004 Location: United States Status: Offline Points: 11127 |
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 Posted: September-10-2022 at 3:00pm |
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Sounds like you have yourself a V7 1/2 engine there.
I'd squirt some oil in that cylinder and check the compression again to give yourself an idea whether it's cylinder head related or piston rings. About an ounce or a little more squirted in, do the test and if the numbers come up a lot, it points toward rings. If they don't come up it would point toward the valves or camshaft lobe worn way down. Remember that metallic noise you girlfriend heard last time it was running right and quit.............she might be onto something.  It should still start and run pretty good as a V7 1/2 though
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AZ86SKI
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Joined: July-05-2022 Location: Phoenix, AZ Status: Offline Points: 115 |
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Posted: September-10-2022 at 4:16pm |
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KENO,
Thank you for the advice! I followed your instructions on squirting some oil into the cylinder and the PSI only came up 10psi from 90 to 100. That doesn't seem like a lot, but I have no idea as I have never done this before. Can I assume I am likely looking at a valve or camshaft lobe problem with only a 10 psi increase? Wishful hoping on my part. Please let me know what you think? Either way I will let the GF know she was right in what she heard when it died. That may be the trick to avoid the look about more upcoming repairs.  Thanks |
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KENO
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Posted: September-10-2022 at 4:48pm |
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Sure seems to point toward valve or camshaft issues, with more chance of it being valves
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63 Skier
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Joined: October-06-2006 Location: Concord, NH Status: Offline Points: 4269 |
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Posted: September-11-2022 at 10:11am |
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So while I don't like that she heard a noise when it shut down, then again you didn't hear it so it couldn't have been too noticable? I would think with 7 cylinders with good, balanced compression, 1 with low but not hole-in-the-piston numbers, 90 psi is still some compression, that the engine would run pretty strong. I wouldn't expect this to be your no-start and dies on the water problems. Plenty of people have run 7 cylinder V-8's for some period of time, and like Ken said yours is a 7 1/2 cylinder given the compression you have, I'd bet that cylinder is firing and making some power. I wish I was more help on your overall issue!
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mrhemi
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Joined: September-02-2009 Location: Canada Status: Offline Points: 30 |
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Posted: September-11-2022 at 1:09pm |
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If you could get a leak down test performed it will give you more information as to what is going on in #7.
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You know you are getting to be vintage when someone says "Back in the day..." and you can dispute their facts.
Mr. Mike. |
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Faceplant
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Joined: July-27-2013 Location: Otter Lake , Mi Status: Offline Points: 418 |
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Posted: September-11-2022 at 9:23pm |
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I ran my boat on 7 cylinders for about a month and a half to get me through the season once. Started fine . Ran just ok. Problem was just a head gasket though.
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Feels like I am hanging 10 but in reality - probably hanging 6.
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AZ86SKI
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Posted: September-16-2022 at 5:27pm |
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I am titling this post "BAD JU JU" which is also likely the new name of this boat. I hope this post does not require me to turn in my CCF man card (assuming I have even earned one here yet), but after I was unable to find a solution to it not re-starting, it was time to take it to a professional shop. This is what they found... 1. The distributor gear had come off the distributor and was sitting down below. The roll pin holding it on was nowhere to be found. They reconnected the gear with a new roll pin. Anyone even heard or seen this before? 2. The rotor was damaged (broken plastic) on one side of the rotor head and the rotor head was slightly bent. I did post earlier that the rotor and cap appeared to be fine which likely led us astray. When I pulled the cap I didn't pull it all the way off as the wires were still attached and the side I was looking at was the non-broken side of the rotor head. They replaced it with a new rotor. 3. While checking TDC with the valve covers off, they noticed that at TDC the intake valve at #1 was about halfway open. Which suggests that possibly the timing chain has slipped. Vacuum was also only at 13 PSI indicating possible incorrect/late valve timing (no vacuum leaks found). The engine now starts and idles but is failing with acceleration on the trailer. Also, the #7 cylinder with the new lower compression after the stall appeared fine from the top side. So it was decision time on how far to go at the shop. I decided to bring it back home and reassess at this point. I am obviously disappointed that all of these problems keep arising on an engine with low hours, but at least some problems have been identified. The noise when it died could have been either the gear coming off or chain slipping, or both. I guess it's possible that the chain had already slipped or was installed wrong causing lack of power issues in the first place, then the gear came off making the noise when it died? My initial thoughts are to tackle removing everything up front and working my way to the timing chain to verify if in fact the timing marks are lined up (or not lined up) as they should be at TDC. How difficult will this job be and any tricks to making the job easier? Does the oil pan need to be loosened or removed to accomplish this task? Again, I want to thank everyone for their input on this now lengthy post, I do appreciate it. Any thoughts or suggestions on the path forward would be appreciated. |
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uncle-buck
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Joined: June-14-2004 Location: United States Status: Offline Points: 331 |
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Posted: September-16-2022 at 8:51pm |
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Check the amount of play in the timing chain by removing belts, spark plugs, and distributor cap, turning the crankshaft, and observing how the dizzy rotor moves.
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1990 Ski Nautique (original owner)
PCM 351W with D.U.I. |
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KENO
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Joined: June-06-2004 Location: United States Status: Offline Points: 11127 |
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Posted: September-17-2022 at 8:10am |
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I guess a good question right about now would be.........how does the engine idle with the distributor back in and the timing set at 10 to 12 degrees or whatever?
If the intake valves are open about halfway when the engine is at TDC, there's no way the engine would run since you wouldn't have any compression at that time. The roll pin is probably laying in the bottom of the oil pan. Pins can break if there's too much load from the oil pump, weak pin or in your case maybe it was a lousy fit and fell out.
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63 Skier
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Joined: October-06-2006 Location: Concord, NH Status: Offline Points: 4269 |
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Posted: September-17-2022 at 10:32am |
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I'm curious about when the distributor gear fell off. You did a compression test that showed good compression on #1, yet how could that be if the intake valve is open at TDC? Something doesn't add up. I know you've already spent an amount of money on parts, and a ton of time on this. You've done an excellent job of following a troubleshooting path but the solution hasn't been as obvious as I might have first thought. The money you've spent isn't wasted, the new parts will serve you well. It might be time to hand off the project to a shop you trust and simply ask them to return a good running 351 to you. You'd definitely want a discussion on scope of work first, but based on what we've been hearing it would be timing set replacement, time the engine, do a compression and leak down test for a health evaluation, at that point ask you if you want it buttoned up in running order or if any other work is recommended.
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AZ86SKI
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Joined: July-05-2022 Location: Phoenix, AZ Status: Offline Points: 115 |
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Posted: September-17-2022 at 1:07pm |
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Thanks fellas. Your feedback makes perfect sense that if the intake valve was halfway open at TDC it wouldn't have enough compression to run and my compression test on number 1 was fine. So, I am more confused on that issue now as well.
I guess the good news is that the distributor issue was identified and we know it at least starts again. Perhaps I can start back at the basics and start down the troubleshooting path again. There was some confusion from the shop on the firing order and the reverse rotation/right hand rotation engine. I believe a ford motor was out of the norm to what they normally serviced. I provided the correct firing order 1-8-4-5-6-2-7-3. That is what I believe is correct for this 351W if someone can confirm. In pondering over the engine this am (but not starting it) the firing order appears to be different now after it came back from the shop. It is now 2-7-3-1-8-4-5-6. The distributor also appears to be rotated more clockwise than it was before. I am very confused as to why. I am beginning to second guess myself so I apologize if I ask questions I should already know the answer to. Can someone confirm for me the correct firing order and also where I have marked #1 in the photo as the #1 wire position/location? Thanks again.  |
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63 Skier
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Joined: October-06-2006 Location: Concord, NH Status: Offline Points: 4269 |
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Posted: September-17-2022 at 1:56pm |
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I'm going to let someone else confirm the firing order so I don't mess anything up ... but if the gear dropped, was re-installed and distributor reinstalled at a noticeably different location, and the firing order is different than before ... there's a lot that can be going wrong timing-wise without the timing chain being the culprit.
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uncle-buck
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Posted: September-17-2022 at 2:09pm |
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The correct firing order for a right hand rotation Ford 351W engine is: 1-8-4-5-6-2-7-3.
Is that the engine you have? You wrote, "the firing order appears to be different now after it came back from the shop. It is now 2-7-3-1-8-4-5-6." That is precisely the same (and correct) firing order, assuming you have a RH 351W engine. It is merely expressed in a different way. You want to make sure you know where top dead center on cylinder no. 1 is and make sure it is the compression stroke (and not the exhaust stroke). When you are certain cylinder no. 1 is at TDC, observe where the distributor rotor is pointing. That's where the spark plug wire for cylinder no. 1 should be. Moving counterclockwise, the wire for no. 8 should be one position over. Then no. 4 and so on. The spark plug wire you marked in the photo as cylinder no. 1 may be correct, *but* not necessarily. It depends on how the DUI was installed. The installer may not have installed it with the rotor pointing at its former location. Which could explain why the rotation of the distributor now looks different. As long as the rotor is pointing to the no. 1 wire when cyl no. 1 is at TDC, and the order of the other wires is correct, you should be good. And I would still check for a loose timing chain without taking the timing chain cover off.   |
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1990 Ski Nautique (original owner)
PCM 351W with D.U.I. |
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AZ86SKI
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Posted: September-17-2022 at 3:12pm |
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Thanks fellas! I really appreciate it. I will check TDC at #1 again and make sure it looks correct and verify the firing order. If so, then I will move on to Uncle Buck's advice on checking the timing chain without removing the timing cover. It may take me a few days to get to the timing chain check done but I will let you guys know what I find. Thanks again.
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AZ86SKI
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Posted: September-17-2022 at 5:15pm |
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Well, my curiosity got the best of me and I decided to tackle these items today.
At TDC on the compression stroke the rotor was in fact pointing to the number 1 wire position (just now in new location) and the firing order was correct the rest of the way around counterclockwise. The advance also moved freely. So we should be good there. I removed the plugs and belts and rotated the engine by hand. The rotor (assuming same as dizzy) seemed to move smoothly. When I paused and reversed the rotation there was maybe about a 1/4" to 3/8" of play before it rotated the other direction. I also measured it in degrees of timing on the timing tape and it was about 5 to 6 degrees, which is likely more accurate than my guess, before it engaged again going the other way. Since this is my first time doing this, any thoughts on these findings? The motor also shows 409 hours for reference. Thanks |
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KENO
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Posted: September-17-2022 at 6:33pm |
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Short answer..............no timing chain problem
Being a 351 Commander it's easy to remove a valve cover without any exhaust manifold interference, so I think you should hopefully verify for yourself that the #1 valves are both closed at TDC on the compression stroke and that the intake isn't half open.
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AZ86SKI
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Posted: September-17-2022 at 6:51pm |
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Yes! Small victory on the timing chain issue! I'll take any victory at this point.
Great advice on removing the valve covers and verifying myself what is going on with the valves as you suggest. Valves are new territory for me but time to learn and confirm. I should also note that there is/was what appeared some red silicone/sealant under the valve covers and manifold (but not where the heads meet the block) which may indicate that someone prior had been in at least those areas previously. The last shop removed it and replaced it with the proper gaskets under the valve covers. Just FYI if that seems important moving forward. I will remove the valve cover for #1 and and rotate the engine and let you know what I find. Thanks! |
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MrMcD
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Joined: January-28-2014 Location: Folsom, CA Status: Offline Points: 3750 |
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Posted: September-18-2022 at 2:45am |
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If you have compression and #1 is getting spark at TDC for #1 the engine should run fine. The fact that you have compression, even 90 PSI says both valves are closed at the perfect time.
Have you been able to start it yet after the shop visit. A cam shaft going flat could reduce or even eliminate a valve opening as it should but the valve would not hang open. A stuck valve could hang a valve open. The most common cause I witnessed causing valves to stick is running an engine on OLD gasoline. Old being 9 mos or older. The older it is the more trouble it can cause. Old gas can shellac the piston head and the vavle stems making them stick in the valve guides. Only cure is to tear down and clean the parts up removing the sticky old gas mess. Flat camshafts are not quiet, the valves get noisy as the lobe goes flat, I don’t think you mentioned any odd running noises, clacking or tapping noises. Having 90 PSI in just one cylinder might foul out a plug after many hours of use but would be mostly not noticed and the engine would run fine till the plug fouled out. My guess is either you have a valve sticking or your shop gave you poor advice about the valve being stuck open. Maybe another cylinder is stuck open not #1? The advice to pull the vavle covers and check the rocker arms and push rods is good. You just have to check each cylinder on compression stroke at TDC for that cylinder. Start with #1, then rotate the engine by hand 90* and check each cylinder in order of the fire order one after the other. 90* turn to reach each cylinder TDC. In your 4 stroke engine it takes 2 full revolutions to check all 8 cylinders. At TDC on compression stroke you will find each rocker arm tight with not much play but just a hair of wiggle in them. If you find one moving a lot up and down with gentle pressure at TDC you found a problem.
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MourningWood
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Posted: September-18-2022 at 11:58am |
A compression test is all mechanical and unaffected by timing, right or wrong. Twice (with a Ford 302) I've had the distributor gear roll-pin break. The gear had just enough interference fit to time the engine accurately. Halfway through second lap the engine lost power and eventually died. (gear moved slightly). Re-time, re-fail. It doesn't matter where the gear is rotationally, just the depth on the shaft to engage the cam gear correctly. (and provide freeplay). The solution was a hardened roll pin. |
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1964 Dunphy X-55 "One 'N Dun"
'I measured twice, cut three times, and it's still too short!" |
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AZ86SKI
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Posted: September-18-2022 at 12:24pm |
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I removed the valve covers and checked the #1 valves at TDC on the compression stroke and both valves were in fact closed as you can see below. In rotating the engine CCW I observed the exhaust valve open then close, the intake valve open then close and both remained closed at TDC. Not sure what the shop was looking at but they are both closed at TDC. Thank you for the guidance on helping me confirm this for myself.
I then checked the remaining cylinders and watched the valves open and close. I'm not sure that I did it correctly for TDC for each cylinder but all of the valves opened and closed the same as #1. All the valves appear functioning the same and damage free. All of the valves looked identical to the #1 valves in the photo below. I did not find any loose springs, they were all tight with no play at all, even when closed. Anything else I should check while everything is apart? Thanks everyone.  |
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uncle-buck
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Posted: September-18-2022 at 12:53pm |
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MourningWood's solution of a hardened roll pin on the distributor gear sounds good.
Seems like the engine should now start and run. Are you getting a good 12 volts to the DUI? |
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1990 Ski Nautique (original owner)
PCM 351W with D.U.I. |
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KENO
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Posted: September-18-2022 at 3:46pm |
Umm Buck................his engine runs again,doesn't run right, backtrack a little with your reading
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uncle-buck
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Posted: September-18-2022 at 4:35pm |
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By "run" I meant run correctly.
This situation has turned into a real tarbaby and I feel bad for him. But I have confidence you can guide him to a successful resolution if he stays with it. |
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1990 Ski Nautique (original owner)
PCM 351W with D.U.I. |
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63 Skier
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Posted: September-18-2022 at 6:17pm |
Going back to your after-the-shop post ... You said it starts and idles but is failing with acceleration on the trailer. You don't mention (unless I missed it) what they found for timing at idle when running. Was it verified? The rotor was broken and replaced, but they didn't replace the cap. Did you inspect the cap carefully for cracks? It would be interesting to hear from you exactly what happens as you move the throttle off of idle, does it stumble immediately, can you coax it up to over 1,000 rpm and then it stalls? I'm just trying to think about the basics. I think we've kind of decided that fuel delivery is ok, you've verified valves are not sticking, that leaves ignition.
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AZ86SKI
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Posted: September-19-2022 at 12:11pm |
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I haven't tried to start it since it returned from this last shop. With the "slipped timing tooth theory" at the time I didn't want to damage anything.
The shop reported that it starts and runs on the trailer and advised they had set the initial timing at 10*. They stated when they gave it fuel it would die. They also reported a slight fluctuation and 13 psi of vacuum at idle. They could not find any vacuum leaks either. I have not confirmed any of this yet. I inspected the cap since the rotor had to hit something to damage it. I didn't see anything but I will give it a very thorough inspection. I missed the damaged rotor before, so lesson learned on my part. I will get everything put back together this week (assuming the cap is good) and hopefully get it started and confirm timing and confirm exactly what is happening when I move the throttle off idle. Also for reference since this post is getting a bit lengthy, I believe this boat has had timing issues in the past since. The reason I say that is the previous distributor I pulled out was an automotive distributor. So the original distributor had already been replaced with the previous distributor or possibly others (I only know about the previous distributor). With only 400 hours that seemed a little odd to me but that is just a guess on my part. The previous distributor also had a chipped tooth on the gear. The chipped tooth is the other piece I found when I removed the old fuel pump. Thanks everyone for your input and patience. I'll let you know what I find when I fire it up...assuming of course that it starts. |
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MourningWood
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Posted: September-19-2022 at 12:37pm |
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You mentioned a couple posts ago about confirming TDC at #1 because the rotor pointed to #1 wire...
Forget the wire. When confirming TDC #1 with valves closed, look at the timing pointer and the marks on the dampener. The position of the #1 wire on the distributor could in fact be part of the problems....
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1964 Dunphy X-55 "One 'N Dun"
'I measured twice, cut three times, and it's still too short!" |
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AZ86SKI
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Posted: September-19-2022 at 5:34pm |
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For clarification in checking TDC, with the #1 spark plug out (closest to the driver's seat). I then rotated the engine by hand CCW with my finger over the the spark plug hole until the pressure began to build. Watched the exhaust valve open then close then intake valve open then close. Then I inserted a long thin ratchet extension into the the same cylinder until it touched the top of the piston. I then continued to rotate the engine until the rachet extension stopped rising to TDC. I then looked at the timing marker which was in-line with the TDC mark on the timing tape on the dampener. I then also checked that the rotor in the distributor was pointing at the #1 wire position.
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uncle-buck
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Posted: September-19-2022 at 7:04pm |
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Are you sure your DUI has a good ground and is getting at least 12 volts to the red wire?
Do you have a copy of the instructions that go with the DUI? If not, you can download it from the Performance Distributors website. It contains some good troubleshooting information. The unit is probably fine, but you may want to double check... |
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1990 Ski Nautique (original owner)
PCM 351W with D.U.I. |
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KENO
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Posted: September-19-2022 at 8:28pm |
Looking at your picture above with the #1 plug wire marked by the piece of paper and working my way around the cap counterclockwise, i can't come up with what looks like the right firing order based on which 4 wires are going to one side of the engine and which 4 go to the other side. It might have something to do with the hallucinogenic mushroom pizza I had for supper, then again maybe the order just ain't right Those mushrooms are still affecting me but it sorta looks like #3 and #5 plug wires are swapped That might make your engine a V6 or maybe V5 1/2 with the low compression on #7. |
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uncle-buck
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Posted: September-19-2022 at 8:40pm |
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Good catch, Ken!
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1990 Ski Nautique (original owner)
PCM 351W with D.U.I. |
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AZ86SKI wrote: