Thanks guys!! I think you guys are on the right track with the fuel delivery system. Going to start there..

It absolutely does. Beyond opening the TB blades and allowing more air in readings from the TPS cause the ECM to go into flood clear mode which shuts off the injector drivers so no more fuel is added.

wybmabilty hit it spot on with hot soak flood condition. I've had this happen as well thinking it was vapor lock. It is NOT vapor lock. Motor is flooded pure and simple. How it happens depends. The injector issues addressed are one possibility. Depending on the fuel system, pump configuration and plumbing there are some times vent lines that vent vapors into the manifold causing the same condition. I know this happens on VST equipped motors and is often mistaken for vapor lock.

Makes complete sense to me. The engine behaves like its flooded. You guys are probably right. Going to check the fuel pressure this weekend and see where that leads. I'm suspicious of the injectors. They were sent out to be repaired when the engine was being reassembled. Thanks!!

I have zero personal experience here, but have read a few threads where when the injectors are sent out for tuning/cleaning they come back a little sticky from the detergents they use. That seems wonky to me, but there you go.

It's true. Have gone thru many vendors over the years where I've had sticking injector issues.

Those that didn't, won't tell me what they use. Damn it. Makes it hard to find other vendors that will have issues or not.

BTW: we all know gasoline is flammable, therefore injectors won't typically be sent with fuel in them, thus why other fluids.

Put a new short block in one of my engines last year swapped all necessary parts
525 efi motors also ..in the heat exchanger there is a temp sender somehow in between pulling the old motor and rigging the new motor it went bad .. I could start the motor cold and if I let it run any more than 10 min it would not restart again unless I waited an hr or so .. If I held throttle wide open( clear flood mode ) it would restart after a lot of cranking .. Turns out temp sensor was the only issue .. Motor simply thought it was cold and dumps more fuel even when warm ..they have a new design temp switch .. Early ones were all plastic the replacement is brass. ..u have to remove heat exchanger to get at it

I can start the motor at any time, it just takes a lot of cranking to get it to fire after its been running and sitting for a while. If I run and then immediately try to restart, it fires right up. The only time I have the problem is when it's been run and then sitting for an extended period of time, like an hour or more.

yes the same with mine I could start it anytime but a lot of cranking also .however when cold fires right off

Are you referring to #36 in this diagram? If so, wouldn't SmartCraft detect that the sensor was bad?

[ATTACH=CONFIG]530194[/ATTACH]

http://www.mercruiserparts.com/Show_...tem+Components

I had the same problem with the engine yesterday... cold start fired right up... ran her for 15 minutes, let sit for 2 hours and it took me 4 turns of the key to get her to fire.. I hooked up a fuel pressure tester yesterday to test the leaky injector theory. Got around 40 psi at idle and it took over 2 hours for the pressure to bleed down to around 16 psi and then I let the pressure out manually. I would think that if the injectors were leaking, the pressure would bleed off much faster than that. I think I will try to replace the temp sensor on the chance that Smokin Gun's theory is right, but any other ideas?