Vapor / Air lock Help !! ????
 

I have a 2000 Baja H2X with 7.4L MPI. Twice recently I have had trouble restarting after running it for a several minute ride. The first time it re-started after about 10 minutets and several times tryings to start. Today it finally started after 3 hours and getting towed in. Once it starts it runs fine. Has anyone else had any similar problems. What are possible solutions ???

Sounds like vapor lock.

Do you have the mechanical pump on your sea pump assy?

If not you need the electric pump upgrade kit.

Try ideling the engine for a few minutes before shutting down, along with opening the hatch if you can and see if that reduces the problem.

Definitely sounds like vapor lock. As mentioned, you can install the electric fuel pump upgrade from Merc or you can return the fuel to the tank instead of the filter head. Right now, the fuel runs in a loop and returns to the water seperator/fuel filter head. If you take the return from there and send it back to the tank, it will stop the vapor locking.
Eddie

E10 fuel will also vaporlock much easier.

I think I have the same problem with one motor. After sitting with genny running for a while, heat builds up under hatch. I leave blowers running all the time.

Port always starts and runs fine.
Starboard will start and run till the carb is empty. I have tried running higher rpm right away, but still does not work.
Pull the full line off and no full (new mechanical pump last yr)

If I pour fuel down the carb a couple times I usually can get it going. Or I leave hatch open for a while to cool down.

My question is, I have considered replacing the steel line with a rubber, steel braided line.

Any thoughts it this may work?

You are not really vapor locking. Carbed engines don't really vaporlock. It sounds like the fuel pump is loosing its prime and allowing the fuel in the lines to drain back to the tank.

I've been battling the same problem with my Baja 454 EFI-running great, pull into a cove or dock for a little while, go to leave and it either won't start, or will start then die shortly after. I finally got it to die on the hose in the garage, checked fuel pressure and found it right at 7psi (about what mechanical pump pressure is) and had power to the pressure pump so I figured the high pressure pump in VST was bad- replaced it-still died the next weekend :rolleyes:. While literally dead in the water, cracked the outlet fuel line loose and cranked the motor-barely pushing any fuel out of mechanical pump-so I figured the mechanical/low pressure pump was junk too. Well, all was fine and dandy for a couple runs untill last weekend, damn thing died again! :eek: I have spent hours going over the fuel system on my boat/engine and have decided it's simply vapor locking. After many hours of research on this "vapor lock" issue, I agree with obnoxious- there should be a fuel return line ran back to the tank! I would double check the "simple" things, but sounds like you are experiancing vapor lock as well.

Can you tell me the part number for the electric fuel pump upgrade?

Take Eddie's suggestion he fixed mine a couple of summers ago and I have never had a vapor lock problem again. Trust me getting caught 20 miles down the lake from the ramp with your wife and two kids on a 95 degree day is not something you want to do twice!!