5.7 l 350 mpi 2003 mercruiser low pressure fuel pum

[RD9]

Hey guys my low pressure pump stopped working but my mechanic seems stumped. When I cycle the ignition switch on the pump won’t pump. My mechanic seems to believe it possibly could be and electrical issue since it occasionally will kick on. 

 

Any sort of module we might be missing. It’s like the pump is not getting power. 

 

[sherman brown]

sounds like a bad pump. when the electric pump was going bad in my car it worked at times then would just stop working until it got to where it wouldnt work at all.

[tech2526]

Unplug the pump and wire in a headlamp bulb. If the light is bright replace the pump. If dim find the corrosion. Easy peasy!. Let us know what you find

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[lrg355]

I had a 5.7 mpi inboard that had fuel pump issues. Maria told me it was the pump. MARINA Ordered pump and waited for delivery. It didn't make the usual running noise when the key was turned on but not started. I decided to look at the wiring diagram and there was a fuse but it wasn't obvious where it was. I took the wires off the pump and wired it directly to the battery. Voila, the pump ran and the engine started. Now, find the fuse!. It was in a fuse holder on top of the engine. It had a 8 amp fuse where I believe a 12 is needed. The fuse was partially burned and would make sometimes make contact when cold but open when warmed up. I wont go to that marina any more after their diagnosis that would have cost about 1200 bucks and still not solve the problem. Wont mention any names. Try jumping directly to battery to see if it runs before spending big bucks. Don't remember wire colors but there is a connector on the pump itself. You can disconnect there and wire directly. Use a fuse on your jumper. Sold the boat a few years ago. Check the wiring diagram on line if you don't have it.

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[RD9]

Appreciate the comments it was a fuel pump.