1997 Ski Nautique Ford 351PCM Won't Start

[97nautique*]

Alright so I have yet another update. The compression tests came out weird. I would be getting 120ish on one cylinder then test that same cylinder again and get like 60. I think it has to do with my tool not fitting properly in the block. Anyways I couldn't find a leak tester as Harbor Freight was out of stock within 20 miles of me. But I still wanted to just look at the inside of the manifold and riser so I took the riser off and only broke 1 bolt. I have some pictures of just how bad it is below. It appears that the gasket was shot and the manifold and riser. This is because it rotted away and there is an 1/8 inch gap on about 3 of the water holes where the water can just slip through even if there was a good gasket. I am going to go ahead and buy a new manifold and riser plus the gaskets and hardware needed. I am doing this only for the starboard side for now. Thanks to everyone for the help and advice. I will probably be back on this thread when I am done with the installation of new parts.

[Peter6000]

That better than a engine rebuild I would consider replacing them both advatually.
When the manifault is off take a good look at that valves water intrusion could have created some rust on the valves especially salt water.
Spinn the motor by hand and make sure the move.
If you get a leak tester test with the manifault off to monitor the exhaust valves.

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[NautiqueJeff]

I fixed the pictures for you.

Wow, that's pretty bad.

That's lots of salt water use with very little if any flushing.

Can't believe you only broke one bolt! Very lucky and very cool!

I hope the water passages inside the engine are in better shape.

[Peter6000]

I couldn't see the pics early that is bad I'm suprised it was still running.

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[97nautique*]

Thanks for the fix on the pics Jeff. I am also surprised at the fact this thing could run with that much water being allowed inside. The other manifold and riser set will be done this fall.

[SilentSeven]

GIven that you had water in the cylinders and you are waiting on parts, I'd be sure to inject a shot of 30w oil in each plug hole and hand crank the engine over. This should help mitigate any additional damage while the engine is down. Sorry if this a captain obvious item....

[97nautique*]

GIven that you had water in the cylinders and you are waiting on parts, I'd be sure to inject a shot of 30w oil in each plug hole and hand crank the engine over. This should help mitigate any additional damage while the engine is down. Sorry if this a captain obvious item....

I will do this now, didn't think of that.

[SilentSeven]

So I read this thread end to end and there's a lot of good advice in here. If this was my boat, here's what I would do.

First, determine if you had a hydro-lock event. I would classify them as a "engine was running and it locked" (quite bad) vs "engine was attempting to start" (less bad). If you locked with the engine was running, it's possible you have internal damage. If this occurred during a starting attempt, you may be lucky enough to either have only damaged the starter or nothing at all. Was the engine knocking in any way after the event - that would be a red flag to go any further. This is just a risk item you are going to have to assess before you do anything more.

Re corrosion damage in the block, you might be able to get some insight by pulling the thermostat housing and poking around. Also, look carefully at the engine block freeze plugs....any replacements or leaks marks around the plugs are warning sign. Again, you'll just have to make a gut call if you're OK to move forward. My guess...corrosion damage will be there but it won't be bad enough to be fatal.

From looking at plug pic, it's hard to tell if there is an engine condition issue...they are all varied in color - some are white, some too dark which is not good. White typically is water which correlates with the water problem. Dark is rich mixture (tune) or oil (engine condition issue). Since it was running crappy prior, hard to say if the colors are indicative of the overall engine consideration or the just the recent problem. Again, something to consider.

If you decide you can move forward, then I would

- Pull the second manifold. Given the condition of one, the other is likely just as damaged.
- Plan to run the following tests before investing in new manifolds
- Compression test - from memory, they should pump about 120lbs each
- For any low compression hole, do a leak down to help ID what the problem is - valves, head gasket or rings.
- Assuming you have reasonable compression in all 8, then order up the manifolds, risers and install.
- See if you can start the motor and it doesn't make horrible rod knocking sounds and you show no block type water leaks. It likely won't run great.
- See what oil pressure you have when it starts. Cold, you have around 40 lbs. My 1600 hour GT-40 (ran like a champ) would go to 20 lbs at idle once it was warmed up (ski pull or two). I'd say anything below 40 lbs cold is also a warning sign of possible engine condition issues..likely bearing wear due to lack of oil changes or even abuse.
- If you make past this point, then I'd do a wholesale no holds barred tune-up. Plugs, wires, cap, fluid flush, impeller change, necessary hose replacements, PVC valve and block fitting, fuel filter change, throttle body clean out, engine ground clean-up, thermostat change all while doing a super careful eyeballing for other compounding issues (corroded connections, etc). When I had run problems on my GT-40 (@1400 hours) it was fixed by swapping in a rebuild distributor as the hall sensor was flakey (you can get one for about $100 via NAPA btw, you don't need a PCM). Others at this hour range have also seen benefits from a distributor replacement. All this is under the assumption that this boat likely has had none of this done and it's all likely over due. The history of salt water use just exacerbates the situation.

And finally, while I did all the above, I'd get out a can of black engine paint and just clean up and paint all the bits as you went through them. There's always good karma to had from a clean and ship shape engine!

Hope this helps....and fingers crossed for a good outcome.

[97nautique*]

The boats parts came in and have been installed. Parts being manifold and manifold gasket, riser and riser gasket along with hardware, and new wet exhaust tubing coming off of the riser. All was installed and went smoothly. I didn't have the right connector for the water hookup so seeing as the boat ramp is only 200ft away I just decided to launch it. The boat fired right up at the ramp and ran awesome. Went out for a test run at around 5mph around the lake and after that took it 30+mph around again. All checked out on the run no leaks or odd sounds. The oil pressure was around 45-60 warm which seems OK. So after running it for the evening I put it on the dock and covered it. Went out next morning and the boat just wouldn't' start. I pulled all the plugs and there was no water coming out any cylinders. Only thing I found there was the port side having darker plugs then the starboard side. I checked the spark on one plug from each side and got strong sparking. Then I poked the fuel check valve in and fuel came shooting out so I know I have fuel. Correct me if I'm wrong but if I have fuel and spark in the same cylinder then it should run ... right? I have no idea what's happening and any help would be nice.

[Peter6000]

I would still check fuel pressure and timing, especially for leaking injectors considering the history.
Install fuel pressure tester turn on ignition after the pumps stop you should have pressure for at least 10 min. Mine stays above 30 psi for about 30min.
How old is your gas?

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[97nautique*]

I'd need a tool to test the pressure right? And to check the timing I'd need a timing gun, and the boat running... correct? I've never checked timing, only cleaned and gapped points on small engine repair. The gas is not even a week old.

[Peter6000]

I'd need a tool to test the pressure right? And to check the timing I'd need a timing gun, and the boat running... correct? I've never checked timing, only cleaned and gapped points on small engine repair. The gas is not even a week old.

I would get the tools I got a fuel pressure tester from harbour freight, you may get a timing light there as well. A cheap spark power tester comes handy as well.
I leave these in the boat just in case.
To check timing you need to pull the spout connecter then it should be fixed 10deg.
With the spout connector in the ecu will control advance ads another 5 deg or so at idle speed and goes to about 30 at higher rpm.

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[97nautique*]

Ok thanks, I will get the spark tester and fuel pressure gauge tomorrow. What do you mean by spout and where is it on the engine? How strong is the spark that you throw out? I sure hope I can even get it running to check the timing!

[Peter6000]

Ok thanks, I will get the spark tester and fuel pressure gauge tomorrow. What do you mean by spout and where is it on the engine? How strong is the spark that you throw out? I sure hope I can even get it running to check the timing!

I use one of these

https://shop.advanceautoparts.com/p/...E&gclsrc=aw.ds

I can open it almost all the way when in line to the spark plug engine cranking
If you get it to 50% you good.

Spout connector it's in front of the ignition coil.







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[97nautique*]

I got both of the testers today. I did the spark test and got it to jump about 3/4 of the way. I did the fuel pressure test and it held at about 35 psi. What do I do now? The engine should run in theory but it is not running. One thing to add is that when I go to start it for the first time it kinda starts for about a second but after that it doesn't try to go.