TROR

Ok, I read in my factory manual that upon doing routine maintenance to check the fluid in the fuel pump/sea pump assembly, after changing the engine oil, I checked it ( little screw on side of housing), there seems to be oil/fuel in both and over full. Obviously I need to replace both mechanical fuel pumps, but I have had no issues with drivability. Anyone have issues or know about this?

Griff

That is pretty normal to have some fuel seep into the lube, especially if it hasn't been changed for several years.
Just drain and change the lube. Use Merc HP drive lube.

apollard

Ditto. All fuel pump diaphragms leak small amounts of fuel. That is why the oil needs to be changed yearly.

Revelocity

I'd check fluid level shortly after you replaced the fluid to assure your diaphragms aren't bad. The Mercury diaphragms don't hold up well to ethanol fuel and unfortunately fail prematurely. Be sure to check replacement fuel pumps as well as I've had to return 2 or 3 due to immediate leakage! The bad diaphragms can result in vapor lock in the 500 EFI also.

thirdchildhood

iTrader: (6)

Yep.

TROR

Thanks for the info ! I will change it out and monitor it.

1989mach1

Do all 500efis have this setup. I was not aware of this.

VoodooRob

Yes, 500 and 525 EFI. Always change the lube when changing oil, it only takes a few minutes with a mity-vac. As a matter of course I change impeller, impeller housing, and change oil in pump when doing an oil change.

JaayTeee

Some of the very first 500efi's 99-00 didn't have them.

Pwraddr

Curious how often you change your oil.