1975 20HP Mercury: Gear Lube Won't Go In

[OhSnap]

I have a 1975 Mercury 20HP outboard. I drained the gear lube out with no problems, but when I tried to refill it the lube won't pump in. It pressurizes and blows off the hose from the hand pump. Almost like the top vent plug is still in.

 

[Laddies]

Re: 1975 20HP Mercury: Gear Lube Won't Go In

It probably is, that large top plug is a flush plug there is a small vent screw on that engine look again.

 

[OhSnap]

Re: 1975 20HP Mercury: Gear Lube Won't Go In

It probably is, that large top plug is a flush plug there is a small vent screw on that engine look again.

I wondered what that little screw was for. I didn't dare remove it. I will give that a shot and see how it goes. I will post the results... Thanks!

 

[OhSnap]

Re: 1975 20HP Mercury: Gear Lube Won't Go In

That worked! Thanks again for your help!