Clogged Fuel Boost Pump Screen (350 MAG MPI)

thbouro

thbouro

Member
Jan 6, 2011
98
VA Beach, VA
Boat Info
310 Sundancer 2001, Raymarine A65, Lowrance HDS 9 Gen 2 Touch, Raymarine Evolution EV-200 A/P
Engines
350 Mercruiser Mag MPI V-Drive
Hello,

I have a 2001 310 SD with twin Mercruiser 350 MAG MPI (V-Drive).

While troubleshooting a RPM drop while on cruise speed, I found debris in the fuel boost pump screen.

My mech suggested to install an extra fuel-water separator filter with inspection bowl between the fuel tank and the boost pump. My only doubt is that, according to the engine's service manual, no extra filter should be installed.

Has anybody faced he same problem and installed an extra filter? What type of filter? Results?


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Check the gas thread someone just posted this same question


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cant use anything with plastic in it on the engine room. The insides of the fuel pumps were painted with black paint. Is this what your finding?
 
I can't be sure about the nature of the debris, it was something very soft, dark brown, melted when pressed. Definitely large enough to clog the pump screen!

Bt Doctur said:
cant use anything with plastic in it on the engine room. The insides of the fuel pumps were painted with black paint. Is this what your finding?
Click to expand...
 
Good point, I think I have read about this possibility somewhere in the forum. How could I check it? The outside surface of the fuel line seems to be fine

scoflaw said:
Could also be your tank to pump fuel lines failing from the inside out
Click to expand...
 
What's the history of fuel usage with this boat ? If the PO had been using non-ethanol for 15 years, You buy it and start using ethanol fuel , that certainly could be the cause. I don't see a black fuel line turning brown, but unsure.
 
Finally I installed a fuel-water separating filter just after the fuel pick up on the tank and before the boost pump and guess what? In both engines the boost pump could not pump the fuel from the tank. I removed the pumps closer to the new filters and everything worked perfectly. I made a sea trial (more than an hour with cruise speed - high demand) and everything was smooth. I believe the clogged screen was the reason for the loss of thrust that I experienced last summer while on high rpm...


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