350 mpi

[bighh7]

Ive got a Sea ray with a 350 MPI and at 2500 - 3000 rpm she is surging , Ive changed the fuel regulator and am still getting between 38 and 43 psi fuel pressure under load . Ive found what I think is a fuel shut off solenoid wich is not connected to 12v . o these motors need a low pressure pump to assist the Mec high pressure pump ? Im banging my head on this one , any ideas ?

 

[CharlieB]

Re: 350 mpi

Sorry, wrong forum, this should be in the Mercruiser forum.

Moderators, please move this to the correct forum so the I/O guys can help him figure this one out!

 

[achris]

Re: 350 mpi

...a 350 MPI and at 2500 - 3000 rpm she is surging ...

43psi is spec, so I doubt that's your problem.

When were the spark plugs last changed? I know you have 'long-life' iridium plugs, and although the book says they last 10 years, they don't!

Chris......

 

[Don S]

Re: 350 mpi

Do you have an Mercruiser serial number for your engine? All MPI's are not the same.

 

[Scott Danforth]

Re: 350 mpi

if your fuel pressure is surging, you may have a supply issue. either the in-tank pickup filter is plugged, the fuel filter is plugged, or your pump is going. fuel pressure should be steady and should not vary with load.

 

[bighh7]

Re: 350 mpi

Thanks for the reply , changed the plugs and leads . I also was told to hook up a low pressure fuel pump and still no change . I also changed the fuel regulator . Im gonna check the fuel tank check valve tomorrow and see if it helps .

 

[bighh7]

Re: 350 mpi

Thanks Im gonna check my fuel supply tomorrow

 

[Don S]

Re: 350 mpi

What about the serial number? Like I said before, not all MPI's are the same, nor do they all have the same fuel pressure. They also don't have fuel shut off valves.

 

[bighh7]

Re: 350 mpi

Sorry the serial # is 0W343313 , thanks again

 

[Don S]

Re: 350 mpi

Sorry the serial # is 0W343313 , thanks again

Better re-check your numbers, that SN is for a carbed 4.3L engine.

 

[cyclops2]

Re: 350 mpi

HMMM

Could 38 to 43 PSI cause a carburator to surge ???