starting problems when hot

[goodewd]

I have a 95 Nautique with the fuel injected GT40 engine (I think it is a non-FCC). After sitting overnight, the engine starts just fine and runs great (the high pressure fuel pump primes when you turn the key and pressures the fuel system).

After running and getting the engine hot, if I sit for awhile, the engine will not start. Mostly because there is no fuel pressure as the hp pump does not prime with I turn the key like usual.

This started happening last summer and I replaced the starter relays but did not seem to solve the problem.

Fast forward to today and took the boat out for the first time this summer. On another note, think I may have a impeller or thermostat problem as the engine overheated as I ran the engine at idle (engine cooled off when running normal). Took it back to the dock and shut off at about 180 temp. Let it sit for about 30 minutes and tried to restart. The hp fuel pump primed, but the engine would not start. Maybe some sort of engine safety to keep from starting over 160. Tried a couple more times and the fuel pump primed but engine would not start. Waited until the engine temp went below 160 and tried to start again. This time, the fuel pump would not prime and engine would kick a little but not start - no fuel pressure just like the original problem.

Obviously have some cooling system work to do, but any advice on the fuel system mystery would be appreciated. Is it time to change the low and high pressure fuel pump or are there any other sensors or switches to try and change out first?

Thanks!

Wilson

[WakeSlayer]

Your cooling problem is an air leak. Tighten all you hose clamps with a nutdriver or ratchet, NOT a screwdriver. You should do this at the very least annually. Verify your strainer is tight and has the gasket. Your cooling issue will be gone.
I am not the sharpest on the fuel systems and will let other chime in. However, in the meantime check your power connections to the pumps. Re-seat the relay. Make sure your lanyard is not flaking out. That shuts off your fuel delivery. If you have to, just jump the purple wires to eliminate that. Also, check your battery voltage, and charging voltage. With a meter, not the gauge.

Good luck.

[Hyped6]

A good place to start is are you getting spark.

Now this may sound funny but it will help diagnose what may be going on with your engine.
You see, For a fuel injected engine to trigger the injectors/spark and fuel pump it needs to see an rpm signal from the crank sensor (probably in the dizzy)

Now, If crank and have no spark/injectors ticking or fuel pressure then chances are you have something going on in your crank sensor. Even if all your other sensors fail other than RPM (MAP/TPS/ATS) you should still get spark and some sort of injection pulse and fuel pump should prime.

However, If you crank, have injectors ticking and also have spark then that means the ECU is getting a crank signal and is most likely working when hot.

Now the fuel pump will also prime for a few seconds when the ignition is switched, this doesn't mean it is working under crank condition.