Vapor lock on 5.8 HO EFI

I replaced both fuel pumps in my '94 ski last year after having a couple of engine stalling episodes. Seemed to fix problem, but 2 weeks ago we were out and after running for about an hour then sitting for about an hour or so in 92-95 degree air temps we started and were idleing for a few minutes then throttled up to pull up my son on the knee board and the engine sputtered and stalled just like last summer. had to weight with engine compartment open for about 5 min then started and ran great again. i felt the pumps, both very hot from engine heat. I seems like it is vapor locking, no fuel until cools a little. Any body else have this problem? I thought I had it fixed with the new pumps. Any suggestions? Please help! Kerry

Not exactly sure. But it seems fuel related the way it begins to throttle up and then sputter and die. I also took off the spark arrestor last year after it happened the first time and while cranking the engine watched the fuel from injectors. Very little and very spotty comming out until cooled off then better fuel flow and engine started. Runs great other wise. No missing or hard starts. What would be best way to check coil packs? this is the distributorless ignition and throttle body injection (pro-tec) that is no longer supported by PCM. Any other ideas?

1994 Ski Nautique may not have had a FCC. And may have had a external fuel pump ('s) set up.
Also is the fuel lines in the boat original? If so change them out to new.
If the motor was not equipped with a FCC a retro fit would help tremendously your hot soak problem along with new fuel lines.

Are there any relays associated with the fuel pumps on this setup?

If it is vapor lock, how do you fix it?    Remove the fuel line further away from the engine? What is FCC?

Mr. Seal what is a hot soak?   I want to check my fuel pressure. What should the fuel pressure be?

Hot Soak or heat soak, is the phenomenon of the engine getting hotter right after shut down, than it was while it was running. This happens, because, when the engine isn't running, no cooling water is being pumped. So, all the residual heat from the cylinder hot spots, soaks into the whole area and heats up everything.

Makes a lot of sense to me, on potential restrictions, increasing the vacuum, and therefore making it easier for the gasoline to vaporize. Never thought about that with the lines either. Good info.

I wonder, to the original poster, does running the blower constantly have any impact? Just curious, because that would get the hot "air" moving out of the engine compartment anyway.

The PCV valves just let the crankcase vapors get sucked back into the carb for combustion rather than be released externally.

84SN2001 wrote: I have the same problem as slalomjunky. I know its not vapor lock because I have a rubber fuel hose NOT metal going from the fuel pump to the carb.   Im thinking that my fuel pump might be going bad. I have a 1984 PCM 350. Should be the same fuel pump as a truck engine??

You'll need to do a pressure check on the pump. I'd say anything below about 4 PSI and a new pump is needed.

Please, do not put a automotive pump on it. It sounds like you already have other non marine items.

Pete, what is the difference between a marine fuel pump and a automotive fuel pump?

If you've got the 350 Chevy, this is most likely what you want:
http://www.skidim.com/prodinfo.asp?number=CRU97842

Marine fuel items have provisions to take care of potential fuel leaks.