1997 Ski Nautique Ford 351PCM Won't Start

[97nautique*]

Hi all, new to the forums here so if I do something wrong, don't hesitate to tell me. Anyways, I have a 1997 Ski Nautique that will not start. It tries to go and sputters over but will not go. When it is turning over now it seems like the starter is hitting something and stopping, then I crank again and it tries and tries. Just to let you guys know, it is in neutral, the safety lanyard in on, the ignition switch is on, the fuel pump for the EFI is turning on, the engine has full and clean oil, the transmission has LOW oil, and I cleaned all electrical connections (new battery too). I had been using it past 3 weeks or so and the original owner before me used it 1200 hours and had no issues. I skied with it yesterday (6-09-2020) and heard a slight vibration/knock that didn't seem internal, and only occurred at forward idle, once the boat got above idle it stopped. In the past weeks it has had a hard starting spree. Also something to add is that the starboard side riser off the manifold was way over heating about a week ago to the point of boiling water, I limped it to the dock and then cleaned the manifold by taking the drain plug out and running a clothes hangar through it then flushing them out. By doing this I got about a cup (measuring) of nasty corroded metal. After I cleaned the manifold and ran the boat (hard start) the risers were reading 120ish on my temp gun after a ski. Any help is greatly appreciated. Thanks!

[NautiqueJeff]

Which engine? There were several 351 variations that year. Is yours the GT-40?

[97nautique*]

I don’t know what engine it is, is there any way I can verify with you what it may be just from looks or numbers. I think it says boss on the valve covers if that helps.

[Peter6000]

I don’t know what engine it is, is there any way I can verify with you what it may be just from looks or numbers. I think it says boss on the valve covers if that helps.

Take a picture of the engine and post it its most likely a gt40.
The clonking noise and overheating would be my fist worry.
Take all sparkplugs out an compare them may post a picture.
Do a compression test.
Check engine oil for water
If all is good.
Disconnect ignition coil remove all spark plugs and spin the engine with the starter listen for noise. Check oil pressure at the same time.
I would replace the exhaust manifold's cleaning them may works for a short time but will hunt you.
Peter

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[97nautique*]

I will do that shortly, currently its pouring so when that stops I should be able to look at the boat some more.

[97nautique*]

Update:
- Engine is most definitely a GT40 because it says gt40 pro boss on the valve covers and on top of the engine
- The spark plugs need to be replaced. What ones should I get and what is there gap going to be?
- I will do a compression test tomorrow as I need the tool
- Engine oil is clean and newish, has no water
Now here is the fun part, after taking all the spark plugs out and inspecting them, I left them out and cranked the engine. When I do so, the motor turns with no clunking noise so far, it can now make a full revolution and then keep going. But when I am cranking the motor, the starboard side pistons shoot out a watery and brown fuel mixture as pictured below. The port side doesn't do this. I am starting to think that the water is in the starboard cylinders because that same sides manifold may not have been letting the water escape out the exhaust, but I don't know. What do I do from here?

I do not know if you guys can see these image links but I'll give it a shot.

[NautiqueJeff]

You're getting water in your cylinders. That's bad. Like really bad.

The issue where "your starter was hitting something" was the compression raising too high for the starter to be able to turn the engine, because there is water in the cylinders, and water does't compress like air.

You need to find out why this is happening before you attempt to run the engine anymore or you risk the hydrolock condition bending a rod, and then you're in even deeper.

Was the engine winterized last year? I'd look for a cracked water jacket or other freeze damage, based on your location up north.

You might get lucky and find that it is an exhaust riser gasket that failed on the starboard side because of the overheating manifold (which could theoretically allow water to back flow into the cylinders on that side), but it is certain that that engine has some issues. For that manifold to have overheated like that, I would still suspect a past winterization issue, or some substantial salt water use.

Did you just buy this boat?

Any salt water use?

Also, I fixed your images for you. This site doesn't like .heic files. Use another format, like.jpg.

[97nautique*]

The boat was winterized properly beforehand according to the original owner who kept it in storage. Where is the water jacket and how do I check it? I agree with what you said about the overheating manifold and that making a gasket fail. How could I replace said gasket and should I be in the market for new manifolds and risers? I bought the boat about 3 weeks ago. The boat was run in salt water sometimes as the guy before me bought it, used it every now and then in the ocean and at lake George which is fresh water. The owner who I trust on his word says that he flushed the engine with fresh water after every salt water run.
Edit: The boat seems to be a HOG on gas, I don't know if this is normal especially on an EFI.

[NautiqueJeff]

I don't know your friend, but personally I would be pretty upset if a friend sold me a boat with these issues.

I hate to say it, but I really doubt the exhaust riser gasket is your issue. It is possible, but unlikely. To check it, you need to remove the four bolts at the exhaust elbow and remove the risers from the manifolds. The problem is that the bolts will almost certainly break when you try to remove them, especially after salt water use, and you'll end up drilling them out. It is not fun.

Normally, exhaust riser gasket failures will show themselves by a rust stain near the gasket, running down the manifold. They can leak like this for years before they cause any water to enter the cylinders though. I have worked on tons of Nautiques, and I have never had one where an exhaust riser gasket failure led to water in the cylinders. It is possible though. Do you have major rust stains or drip marks here?



These are the gaskets you will need if you do this job:
https://www.nautiqueparts.com/produc...risers-rm0002/

I would certainly advise new risers at least, since they are known to be clogging with rust.

Signs definitely point to this boat not being properly flushed after salt water use, but I still think you probably have another, bigger, issue.

My guess is that after replacing the exhaust riser gaskets, you're still going to have a problem, but I have been wrong plenty of times before.

If the block is cracked, you're looking at replacing the engine, or a very expensive block welding procedure (which I wouldn't even consider on an engine with this many hours and having been used in salt and not maintained).

What was the engine temperature on the gauge when the exhaust was overheating? Is there a chance it was hot enough to blow the head gasket?

[97nautique*]

There is dripping and rust in that area of the risers. The engine temp gauge wasn't really out of the ordinary but I do not trust it. The risers were definitely near or above 200 degrees as my laser temp gun said. The weird thing is, after the overheating issue I cleaned the manifolds as mentioned before and it ran great had no issues for a week except the hard start. I am thinking that I'll replace both risers and gaskets. But before I do this I'm going to do compression tests to make sure there isn't a head gasket failure or some other internal failure (shouldn't be as the boat did run). What should the compression be around for each cylinder? If I end up getting good compression and then go in for the riser and riser gasket replacements, should the manifolds also be replaced as well? Also not a friend really, just a craigslist deal, still aggravating either way.

[NautiqueJeff]

I'm aggravated for you!

I'm concerned that you're thinking of spending $700 on risers and manifolds and still might have a bigger problem that would require a block replacement. I would have someone check the block for cracks before I spent that kind of money.

If you do end up replacing the manifolds and the risers/elbows, at least you wouldn't have to risk breaking off the riser bolts since you'd be replacing both pieces. And it certainly wouldn't hurt to replace both.

I'll tell you, just because the boat was running, that doesn't mean a thing. I am also working on an engine right now that was not properly winterized last year (oddly, from Massachusetts too). I had it running very nicely, but it was spraying water out of a huge crack in the block, and the exhaust manifold freeze plug was popped. When I turned it off, the cylinders started filling with water (just like yours), and I found my big problem. I am having a replacement engine installed in that boat in two weeks. I could walk out there right now and fire up the old one though (but it would probably quickly overheat).

If you're interested in seeing my running engine that has a cracked block, check out the videos in this thread:
https://www.planetnautique.com/vb5/f...803#post610803

[97nautique*]

Is there a way for me to check for a block crack or something along those lines? I really do not think there is a problem in the heads or block because there isn't oil or water spraying out the block and the oil is clean and about a 1/16 inch below the full line. I do not know everything though and am still listening to what you're saying about the possible block issue. So as said I will do a compression test, look for any really obvious block problems. And if all checks out there then I'll go for one new riser and gasket just on the problem side for now. I will be back on this thread tomorrow with an update.

[Peter6000]

Is there a way for me to check for a block crack or something along those lines? I really do not think there is a problem in the heads or block because there isn't oil or water spraying out the block and the oil is clean and about a 1/16 inch below the full line. I do not know everything though and am still listening to what you're saying about the possible block issue. So as said I will do a compression test, look for any really obvious block problems. And if all checks out there then I'll go for one new riser and gasket just on the problem side for now. I will be back on this thread tomorrow with an update.

I think if the water would have come from the riser you would have it in all 4 cylinders on that side. To me this looks more like a blown head gasket or worse.
I can look up the compression values later the are in the manuals look under manuals in this forum.
I would also consider a leak down test it's better than the compression test. You can get a tester for $35 at harbour freight.
If you have a leak you can hear where it is.
I purchased my boat with a simular issue 8y ago had the engine rebuild in a machine shop no problems since.
The gas consumption on the gt40 is better than on any carbonated engine I ever had. And simular to my tige that had a mercruiser fuel injected.
Peter

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[97nautique*]

I will get both tools today and see how my engine checks out. How do I know if there is a head gasket failure since there's no radiator? Where would the air be leaking if it was a bad head gasket? And I do have water in all the starboard cylinders.

[Peter6000]

I will get both tools today and see how my engine checks out. How do I know if there is a head gasket failure since there's no radiator? Where would the air be leaking if it was a bad head gasket? And I do have water in all the starboard cylinders.

That is actually good news so it could be coming from the exhaust.
The leak tester pumps air into the cylinder (you need a compressor by the way).
Carefull with the pressure settings on the compressor read the instructions.
If you hear it coming out of the exhaust you have a exhaust valve issue if you here it in the intake it's the intake valve.
If you hear it in at the oil filler it's bad piston rings.
If it comes from a water channel it's the gasket.
Another test for cooling water leakage would be to take both elbows off, build a plate to cover them watertight and connect a waterhose to the water intake and let it sit for a while then see if you have water in any of the cylinders.


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