cool fuel 350 mag MPI

[sptjet90Reflexx]

Does anyone know if you can delete this mercruiser "cool fuel" system? I dont understand why you cannot just run an electric pump from the tank to the motor with an inline filter..

 

[alldodge]

Does anyone know if you can delete this mercruiser "cool fuel" system? I dont understand why you cannot just run an electric pump from the tank to the motor with an inline filter..

Issue with marine EFI systems is the heat stays in the engine compartment. If heat stays in the compartment, you get vapor lock. The regulator controls the pressure the pump puts out depending on vacuum from the intake. This and other things can be fixed by other means but takes a different design. I fixed mine with a custom design

 

[sptjet90Reflexx]

could you elaborate on your design? my older boats never needed this and I never had vapor lock issues. Really dont want to replace the unit. Paint degraded and ruined the pumps.

 

[alldodge]

The paint coming loose in the pump housing was a big issue for Merc, they had to replace a lot of them due to a bad manufacturing process,

All of the marine EFI systems either have one or two pumps (separate or in one unit). The high pressure pump supplies fuel to the rail and excess pressure not needed by the injectors is sent back to the fuel filter, or to the VST tank. The recirculating fuel gets hot and can start to boil if engine compartment gets to warm.

To fix the issue the excess fuel not needed by the regulator is sent back to the main fuel tank. The regulator on my second Gen cool fuel is no longer used, it uses the regulator on the fuel rail which maintains it at 40 psi. Anything above 40 psi is returned to the fuel tank