Noisy 7.4 MPI fuel pump and/or regulator
 

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??

Re: Noisy 7.4 MPI fuel pump and/or regulator
 

Somebody must know something about this noise!!!

Re: Noisy 7.4 MPI fuel pump and/or regulator
 

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

Re: Noisy 7.4 MPI fuel pump and/or regulator
 

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?

Re: Noisy 7.4 MPI fuel pump and/or regulator
 

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??

Re: Noisy 7.4 MPI fuel pump and/or regulator
 

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.

Re: Noisy 7.4 MPI fuel pump and/or regulator
 

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 :rolleyes:

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.

Re: Noisy 7.4 MPI fuel pump and/or regulator
 

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?