1995 Ski Nautique GT40 EFI doesnt start sometimes when its hot

[DennyG95]

Hello

I have a 1995 Ski Nautique with a GT40 pro Boss EFI PCM engine.

I have owned it since new and has never had always run good and dependable. about 1000 hours on it Last summer it developed starting problems, that is it started hard and sometimes would not start after the engine ran for a while and was hot. I had all the fundamental electrical items replaced – plugs, wires cap, etc. and also the exhaust manifold gaskets were leaking so I replaced those. Ran much better this year but the same trouble continued when it got warm it occasionally wouldn’t start. Brought it to a dealer and they couldn’t replicate the problem, but recommended the fuel pump be replaced. It was the original 2 pump set up and was making noise. I agreed and had that installed.

The boat has never run better – smooth and quick accelerating but….the hard or no starting problem persists. It always starts when cold, but sometimes not or hard (turn it over for quite a while) when it’s hot.

Open to any ideas or relatively inexpensive replacement parts.

Thanks in advance !

[Blamey]

Try searching on Correct Craft Fan. They have a specific post called Poor Mans GT40 Diagnosis, which covers various GT40 issues. I believe this has come up. I can't remember the exact issue but if you haven't replaced your relays, you may want to try those.

When it is hot, do you here the fuel pump run? What happens when you try start? Nothing or does it turn over and not start? Might want to check for fuel pressure at the rail when this happens to see if it's a fuel issue.

You could also be experiencing vapor lock. After 1995 they added the Fuel Control Cell(FCC) to the GT40 to help with this issue.

[DennyG95]

thanks i will try that site

[DennyG95]

it turns over but doesn't fire. seems like its not getting fuel. sometimes it pops and fires and barely stays running.

[Blamey]

If you aren't sure if the relays have been changed might be worth spending the $30 and getting 2. I know you can get them at Napa because it is the say as the car part but I don't know the part number.

Did your dealer replace both the HP and lp fuel pumps. Did they install a FCC?

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[DennyG95]

yes both fuel pumps were replaced. No on the FCC. I will pursue replacing the relays as they are original. Thanks!

[DLafont]

Other possibility could be starter solenoid. Had issues with mine hesitating, i.e. had to hit button many times to get warm boat to start. Changed it and now all good.

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[kmarine]

I had this problem for years with mine, especially after sitting anchored for a half hour or so. What would happen is mine would start and die after the fuel in fuel cell became used up. I replaced the anti siphon valve and low pressure fuel pump to remedy this. It seems the low pressure pump would not work as efficiently when hot. then dead in the water I would have engine compartment open to cool fuel pump as well as a wet towel to cool it down faster. Wait an hour and it would run normal.

[skiharder]

Im going through same issue have a 95 ski with gt-40 runs great then wont start, im looking for the problem now any more good info >>>

[bdub]

'94 GT-40 with EFI - I experienced this as well a couple of summers ago.

I know this may sound strange, but for some reason I felt like it was related to the injectors being 20+ years old and had them cleaned. The problem disappeared after the cleaning.

[skiharder]

Im going through same issue have a 95 ski with gt-40 runs great then wont start, im looking for the problem now any more good info >>>

I posted this awhile ago but I found my problem on my 95 SN GT-40 turns out to be my fuel pressure (pump) for injection, put a guge on it and saw the drop out went from 40psi to 0, but only after it heats up. Changing it out now and will update.

[mf01]

I had the same issue on the TBI Engine. It would start and run fine. If it sat anchored for over an hour it had starting issues. I checked when I got home and had really low PSI. Next morning, after cooling off, it was back to normal PSI. I replaced the low pressure pump and it ran fine until I sold it.

The funny part of it all, is that I had my Dad tow me in with his jetski. This was my only issue with that boat on the water.

[skiharder]

Sorry I didn’t reply until now but my particular problem got solved when I purchased a fuel pressure meter for fuel injection. I went up to the lake and started our day like usual and like before once it got up to running temp I tried to restart and just engine roll over (no start) then I checked fuel pressure at the driver side fuel rail and there was the problem 0’ psi and no fuel pressure. Had to replace hi/low fuel pump and she’s running like a champ....


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