niceguy

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.

Dock Holiday

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

niceguy

Excellent, will do. Thanks guys.

BY U BOY

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

Boat Tech

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.

t500hps

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.

Boat Tech

idea

PURPLE HORNET

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

Rambunctious

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

Old Navy

Running out of gas 1 time probably is not going to fry the motor. The lean "POP" is a reason for concern though, IMO. Read your plugs and look for aluminum or fly specs on them. If you dont see any you're OK. My pump had bad bearings earlier this year and fuel pressure would drop off and the bowls would go dry and the motor would just die out at high rpms. So anyway, you can't buy the pump at napa, But you can rebuild the fuel/sea pump with good success. Buy the parts from merc, press it apart-beware the snap ring under the shaft seal -reassemble, and your done. If you want to save 20 dollars on the bearings, go get 2 #204's from the auto parts store. If you are feeling energetic, you can cross reference the seals too, instead of using the merc parts.