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Inverted fuel pump question

Roadking57

Roadking57

Contributing Member
Eng S/N 0B776858, 1988 4.3L LX. Symptom: Runs on lake at 3/4 throttle all day. When I try full throttle it tries to accelerate then falls flat. Bring back to 3/4 its happy. Starts and idles great. I have rebuilt the carburetor. I think the fuel pump is original. I want to replace it just to eliminate a potential problem. However,
the pump is attached inverted. I have replaced the little stone filter in the bowl. All of the information I can find on the net says it should not be mounted inverted. The V6 block is not the same as a SBC as far as the mount surface. This block mount pad is nearly 45deg slanted.
Did GM design this marine engine with it inverted? What are your thoughts Gentlemen?
 

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Okay, Thank you for the fast reply. If you follow the link to the 2nd pump listed (1st is NLA) Quicksilver P/N 862077A1, it says in the comments mounted with the filter bowl facing down. I am all about buying OEM parts whenever available. Should I buy it and try to mount it like it says? Or am I SOL. Finding the correct mechanical pump bc of NLA status, and just look into a blanking plate and an aftermarket electric pump?
 
I just chatted with a parts tech at boats.net. He confirmed that there is no note or information listed from Mercruiser indicating a change where the pump needs to be mounted opposite of its original orientation. Also confirmed the part number 41141A2 is correct for my engine but has been superceded by 862077A1. I will order the new pump and compare the two arms and bolt patterns and go from there.

Thank you Gentlemen !

Wait! the comment section I referred to is a bit mis-leading! The words say install with filter bowl facing down (when you are looking at it)!!
if you look at the bowl it is facing down. flip the pump upright and its facing up!! Anyone agree??

On this Chevy-derived V6 block, the fuel pump mounts on the lower passenger side of the engine with the filter bowl/body facing downward, which causes the pump to look inverted compared to modern inline configurations (Taken from Google AI)
 
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The bolt pattern & gasket is offset. Regardless of original design they were all (1963 and up) built filter up, 2 series over the years.
If OEM replacement pump is built filter down, then so be it. It can only be bolted on 1 way. If you were buying some Amazon Chineesium pump I'd suggest oars & a big fire extinguisher.
 
Thanks for the input Droid!
Never chineesium for me!! Ive been down that road replacing stuff 2-3 times. No way, I operate this boat full of friends and family, sometimes in the ocean. As a mechanic I prefer quality parts that 1.) Work like they should and 2.) Last like they should.
 
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