Mercruiser Fuel Pump Pressure 861155A2

[bgc]

Had a new one for me last night,

Boat is a 2001, 5.0 with a 2 barrel Rochester. I came in with a heavily fouled carburetor. After a soak and rebuild, it kept flooding and filling the barrels with fuel. Simple enough right? Float/needle and seat issue.
Tore it down 2 more times still happens. Checked the pressure the float/needle will force open at, @7 psi. Checked the pump numbers 861155A2 (this is now superseded by 861155A3), correct pump for this engine configuration. Checked the output pressure of the pump, BINGO! I turned it off at 11 psi.

FWIW/FYI I hope this information can save someone a bit of time.

 

[Don S]

Re: Mercruiser Fuel Pump Pressure 861155A2

You obviously got either a defective pump, or a improperly packaged pump. The fuel pump pressure for your engine is supposed to be 3-7 psi. The A3 is the correct pump number.

Did you buy the new pump from a Merc dealer or an individual off ebay?

Just an FYI, You don't have a Rochester carb, Your carb looks similar, but is actually a Mercarb. You can verify this by looking at the idle mixture screws. Tthe Rochester has 2 screws, while the Mercarb has one.

 

[bgc]

Re: Mercruiser Fuel Pump Pressure 861155A2

The customer brought it in like that. Judging by the lack of marks and condition of the grommets, it was the original pump.

All of our parts come from Mercury, why risk it?