Thought I had a vapor lock issue

[bmxcinci]

Though I was having a vapor lock issue.. until this weekend.. Trailer the boat down to Lake Cumberland.

It fired right up on Saturday morning. Went to a cove, sat for a couple hours and no start. Pop the hatch for an hour or so, and it fired up. I did notice that when it did start that the rpms on the tach were no right. ran for a couple minutes, and the rpms got back to normal. Got out Sunday, and it fired right up, idled over to the marina to fill up and it started but was running rough and the temp seemed a little hot. Filled up and it ran like it was running out of gas. Temp started going up, and then it stalled. No restarting after that.

We tied the boat up, and went out on another boat all day, get back and it still wouldn't start. Trailer home, and go to look at it. fires up first crank.. boat is a 2000 20i with a 350 mercruiser mpi. Any help would be appreciated. Going to change the fuel filter and water separator to start.

[boatwakes]

Ignition coil but you also potentially have a raw water impeller issue. Last tune up? Original ignition sensor module? Fuel pressure? When you turn the key to the on position and the fuel pump cycles, does it sound unhealthy?

[bmxcinci]

Last year was the last tune up. Previous owner but a good friend and i know she paid for it . New impeller this spring. Not sure on the ignition module. Anything I can check.on the coil. Or just go ahead and put a new one on.

[bmxcinci]

Fuel pump sounds healthy.

[bmxcinci]

Tried a new coil.. the other seemed like it might be the original and had some corrosion on the contacts..

Took it to the lake to run it, and it started 2 or 3 times each time running a shorter time and then would slowy stall out. After the third time It would just crank. I had the engine cover off and it seemed like there was an air sound or rushing sound up around the top of the motor? When it ran it ran smooth, I could rev it and go back to idle.

I had also changed the fuel water seperator, as It was on my list to do.

[bmxcinci]

Got the impeller replaced, and all the broken fins out. Not sure why that went. Replaced this spring. Thermostat is also replaced and the temp is nice and steady.

Taking it out this afternoon, and I am bringing a fuel pressure tester to check it if it doesn't start. It seemed to be running good, on the trailer sitting in the water.

[bmxcinci]

Ok took the boat out this afternoon. Started great,, ran great. only showed 26 psi on my tester. slightly low. let it sit, and no start. put the fuel pressure tester on it was 2 psi? everytime I primed the motor it went up 2psi.. finally got to 30 and it started.. I am assuming this is a bad fuel pump..

any other ideas.. I have removed the cover from the cool fuel pump housing and it sounds like it always have, but I had some buddies out with a similar motor and the pumps did not sound the same.

[TeamAllen]

I have had similar symptoms in the past. For me it was vapor lock caused by a hot soak condition. It seems to be more common with the increased ethanol in fuel. To help remedy the situation I use a varied combination of things. Run the blower to cool the engine compartment. Use Marine Sta-Bil in every tank of gas and let the engine idle after a run. That will allow the engine and fuel to cool before you turn the engine off. On my boat I can actually watch the temp gauge drop as it idles for a few minutes after a run.

Maybe it's something else, but it's something else to try? Good luck and keep us updated.