EFI High Pressure Fuel Pump Reservoir

[Jim Marshall]

I picked up a OMC fuel injection system for a Ford 302. It came with the low pressure fuel pump, wiring harnesses, brackets, fuel rails, ECU, etc. but was missing the high pressure fuel pump and the fuel reservoir.

In looking through the manual and some previous iboats articles that there is a High Pressure fuel pump reservoir. It looks like it is fairly complicated in that it circulates cold water to reduce vaporized fuel. It also looks like it has a float, etc.

Can anyone tell me why this is necessary in boats and not in cars. It looks like the same system for Volvo, OMC, and Mercruiser. It also looks like it is more complicated than I would think you would want in a boat.

Thanks,

Jim

 

[flabum]

Re: EFI High Pressure Fuel Pump Reservoir

Boats tend to experience vapor lock more than cars. The vapor seperator takes care of this proble (mostly). New marine engines no longer use this system, they now use a fuel cooler and high pressure pump without the tank.

The tank was used to seperate any vapor that was created while bringing fuel to the engine. The fuel would fill the tank until the float needle closed. As the vapor collected in the tank, the fuel level woul drop and allow the float to drop and allow the vapor to escape out through the float needle. As the vapor escapes, the fuel level would rise and close the needle once again.

Improovements in fuel systems and engine room temparatures slowly eliminated the need for vapor tanks. If you knew the pressure that your system requires, you probably could forgo the vapor seperator setup and get a Merc Cool fuel to take it's place. You may even be able to just get a fuel cooler and a carter high pressure pump and fit it.

 

[Jim Marshall]

Re: EFI High Pressure Fuel Pump Reservoir

Flabum,

Thanks for the explanation. Now it makes sense. Do you know where I could get a Merc Cool?

I also read that later cars (at least) went to an "in tank" fuel pump to get rid of the two pump system. Has that happened in Marine engines?

Thanks again,

Jim Marshall

 

[flabum]

Re: EFI High Pressure Fuel Pump Reservoir

I have seen it in some efi jetboats.