merc lower unit

[clifford69]

Hello I have a 1991 120 hp force OB with a mercury lower unit. I was changing my lower unit grease and noticed it was milky. I noticed there was grease leaking out of a screw on the side of the lower unit. I dont know what its called its the very bottom of the unit,where the propshaft come out, just above the skeg. the screw is located on the forward right side. I tried to tighten it but it just turned so I tried to loosen it and it just turned. My question is what is that screw for. and is there an o-ring in there? thanks cliff

 

[Keith Buchanan]

Re: merc lower unit

That's your drain and the upper one is your vent. Drained lube is generally creamy. When re-filling fill from bottom untill it comes out of the vent.<br /><br />From your post it sounds like the thread of your drain has been compromised. Simply present it to your nearest machine shop/engineering co and they shouln't charge you a great deal to clean and enlarge the thread hole and cut you a new stopper. If they do cut you a new stopper ask them if they can incorporate the magnetic core of your original stopper as this attracts nasties out of your lube whilst running.<br /><br />And by the way there should be an O ring there.<br /><br />Best of luck Keith B..

 

[clifford69]

Re: merc lower unit

it's above the drain plug and below the fill and vent holes. it is located on the side of the rounded part of the lower unit. It's a smaller screw than the drain plug thanks cliff