Ok guys, one mroe question:

When you remove the factory mechanical pump that is mounted on the seawater pump, there is a little oil in there. Do I leave that oil or is there not suppossed be oil in there?

Thanks.

I think that oil is to lubricate the pump arm ??!!

But not shoer ,sorry !

Yes it is supposed to be the. Replace it with fresh oil.

Excellent, will do. Thanks guys.

even if he is blocking it off and using a electric pump?

Yes there needs to be oil in there, and the only oil you should use is mercruisers HP gear lube plus, The same oil you would put in your drive. And you should be changing that oil every time you do a new impeller, becouse some day there might be A good chance you might find some gas in the oil, If there is then the fuel pump diaphragm might have a small hole in it and would be leaking in to the oil area.

Several guys around her have had pump failures and/or found gas in that oil. This winter I pulled mine off and drilled/tapped drains in that pump so I can drain and re-fill the oil in there without taking the whole thing apart anymore.

idea

I change the oil regular in mine. I also put a drain plug in my housing. I always have a trace of gas in their. I even bought a new fuel pump last season because I thought it was bad. Still a trace of gas in their. I talked to a top notch boat mechanic and he said, he has never changed the oil in one of those styles and not found gas in it.

Merc does not sell that diaphragm for the pump anymore. A new pump runs 159-189. Has anybody crossed that diaphragm over with another one. That pump looks like a carter style. Napa also lists the boat fuel pump but no diaphragm.

Just my 02

TTT- this is important info


I just found out the hard way that the oil reservoir needs to be maintained. I did not know there was an oil reservoir

I just squeeked a shaft and slipring ( cam) after the pump went and dumped gas into the reservoir.
the slip ring stopped slipping and began rotating
groudn down the fuel pump lever

slowly lost fuel pressure at 4500 rpm under boost !!!!
slowed to 4000, then 3500, then backfired and I stopped
hoping for no engine damage ( lean burndown)

is the carter pump an automotive pump
merc want about $189? for it
want to know if I can get it at an autoparts store
needed for 525sc

thanks
Ramb