Frustrating problems... Little help please

[crimedog]

So, at the end of last season, I noticed the engine (07 SANTE ex330, 120ish hrs) didn't quite have the power it should. So I changed the 2 fuel filters, cap/rotor, and fluids this winter. I also changed the exhaust manifold gaskets because they were shot. Took the boat out, and it idled rough but once I got the RPM's up, it ran well. So, I changed plugs and wires, found a plug that looked a good bit worse than the others. Went for a test ride, idled much better, accelerated like it should. I did notice that fuel would spray out of the tank vent occasionally, but figured it was because the tank was too full. I took the boat out this afternoon without adding anymore fuel, everything seems fine, but still getting some fuel out the vent. I get up to speed, maybe 3000-3500 RPM, and the engine basically cuts out back to idle, then jumps up again. It never died, but would just totally lose power. It did this a couple times, and then ran fine for about 30-45 mins until it did it again. I am figuring it is a fuel problem, and with the fuel leaking out the vent, we open the tank fill cap, and it's like opening a shook up beer, big rush of air. As we are headed back to dock, the engine decides it is done, and sputters to a halt. Once that happened, we could barely get it to idle and sputters and spits and dies when you put it in gear or give it a little gas. Basically won't run now.

I should say that I did overheat the motor the first time out, and needed to replace the 2 rubber exhaust hoses due to self-inflicted moment of sheer stupidity. I was worried about head gaskets and what-not, but the oil looks good, and the motor was running pretty well, when it wanted too. Also, I have checked the fuel pressure prior to this latest issue, and it was 55ish when energized and sat around 60 when running. I plan on checking it again since this latest mess...

Thanks in advance for any help.

[HS]

Has the fuel been treated with sta - bil for off season storage?

For the forum: Could gelled up fuel cause something like this, and meant the tank shouldbe emptied?

[Fluid63]

Try running it with the fuel filler caps off/loose to see if the eng runs better without the build up of pressure in the tank.
If it runs better check your tank breather for blockage.


Failing that you may have done more damage than was immediately obvious when you got it “Hot”.
If it was hot enough to damage the rubber exhaust than everything else would have been quite hot too.

[crimedog]

I put Sta-Bil in in the tank prior to the winter. We did try to run w/o the filler caps on, and didn't notice any difference.

Have been looking it over today, and found the fuel pressure regulator does not have a vacuum line connected to it. Looking thru the manual, it looks like it should be routed to a port on the intake. But, that port has been capped, assuming from the factory. So the question is, should there be a vacuum line from the regulator to the intake, or should both of those be capped? Right now, the connection on the regulator is not capped.