baronbob

I have what I think is a new noise, mostly noticed @ idle. It sounds like the fuel pump or regulator. The machine, (7.4 MPI), seems to run good but I worry about fuel starvation. Any ideas??

baronbob

Somebody must know something about this noise!!!

SteveO

I discovered the same noise this year. Sounded like it was starving for fuel, kind of a hhhmmming sound or buzzing sound. Even when you first turn the key on this fuel pump sounds like it is dying and the other motor has a nice hum to it. Took everything apart all the way to the fuel pump. Same sound. Replaced the fuel pump. Same sound. So I bought a fuel pres. gauge and checked it comparing it to the other motor. Same pres. Ran it about 5 miles, the boat ran fine.
I think it was always there I just didn't here it.
'98 7.4MPI

baronbob

Thanks for your response. I have heard this sound with other fuel pumps before, without consequences. I am about to depart on a trip through the San Juan islands and will be covering about 500 miles and I don't want any surprises. It sounds like you have a twin and I am certain you thought about moving the parts one @ a time to see which part moves the sound. What fuel pressure gauge did you select and what pressures are you seeing @ idle and then under way?

Pat McPherson

My pump sounded like it was cavitating last year.
Changed the filter, check the pressure, all good.
Still noisy...
This year no noise, go figure??

NEXTASEX

My fuel pump on a 99 7.4 MPI started getting noisy then failed.After it left me stranded the dealer found there was a service bulletin about this pump failing.

SteveO

My fuel pump on a 99 7.4 MPI started getting noisy then failed.After it left me stranded the dealer found there was a service bulletin about this pump failing.

Great

What fuel pressure gauge did you select and what pressures are you seeing @ idle and then under way?

I bought a pres. gauge at Murray's for a GM Motor (about $40). It had a few adapters in it to connect. I can't remember the fuel pres. readings, I just remember they were both the same. 30-35psi? The gauge had some good instructions for trouble shooting the fuel system. I checked with the key on to see if it held a constant pres. then with the motors running, not while under way. Both readings were the same.

baronbob

Did you replace it with the same model pump? I am in the process of up grading with a procharger M-1, Do you think I should increase the pump capacity and what about the regulator?