250 EFI - Vapor Lock/Stalling after starting warm

[Outrageous One]

Engine starts easily when cold and runs flawlessly. After the engine sits for a while, it will restart with no problem, but, after several minutes, it will start to race like it is running lean, (running out of fuel) sputter and die. It will restart and immediately stall out. Squeezing the bulb the first time resulted in a momentary restart and then it stalls again. Pump the bulb again and it restarts and runs flawlessly. Replaced the bulb, fuel water separator, and hoses without curing. I tried to pump the bulb as it was starting to stall, but it still did. I tried pumping the bulb before starting and it still stalled. It always starts after pumping the bulb after the 2nd stall, but never after the first stall. It acts almost like engines from the 70's would do when they vapor locked. High pressure pump has been replaced.

 

[mram10us]

What year? If it has pulse pump, not a bad thing to rebuild. Also, check your fuel tank vent.

 

[Outrageous One]

It's a 2001 with only 350 hours. I was thinking it might be the low pressure fuel pump (pulse pump?) that feeds the high pressure VSP, which has been replaced. My hesitation is that pumping the bulb as it's about to stall doesn't prevent it from doing so. Since my post, it took 5 bulb pump/start attempts before it finally stayed running. New wrinkle: It stalled twice while I was at idle trying to dock once back home. It would appear that whatever is causing the restart problem is now getting worse. When the VSP went bad, it did so in stages - it stalled at 4,000 and would only pull 1,300. The first thing I did was remove and disassemble the low pressure pump which was relatively easy. I found no visible defects and put it back together and the engine ran until the VSP failed altogether. Sounds like there are kits available rather than replacing the whole pump? Source?
Thanks for your response.

 

[mram10us]

Hopefully one of the knowledgeable guys will jump in. I am a novice, but have learned a little due to my engine problems. Get on marine engine.com and input your engine #. Then you can search the part # on ebay. Most guys will ask if your hoses are new from the tanks to the engine. They will also ask about the vacuum lines on the motor. Again, I am no expert, so hopefully someone else will chime in Keep us updated! Nothing worse than helping someone on here and never hearing from them after it's fixed.

 

[Outrageous One]

I'll keep you posted if I can figure out how to navigate this site - your post just now came up even though you wrote it 2 days ago????. Nobody else has responded so I'm going to reach out to some local mechanics. Thanks again

 

[Outrageous One]

Can't find a mechanic here in Cape Coral that isn't booked up for a couple of weeks. In the interim, I spoke to one that believes the problem is electronic. Something is getting hot and will not allow fuel to go to the VSP. The motor starts hot because there is fuel in the VSP reservoir, but it is not replenished. If the "Lift" or low pressure pump were bad, it wouldn't run at all or would perform poorly once running. In addition, pumping the bulb would bypass it. He recommended not replacing anything more in the fuel supply chain. Now all I need to know is what could shut off the fuel when it's hot?