Gearbox seal HELP!!!

[Druther]

Hey all! I hope all is well in your boaters world.

I have a '78 Mercury 85 hp outbourd with milky gearbox oil from water getting. I need to know how to replace the seal behind the prop. I don't think it's leaking onthe top seal.

Any help I would REALLY apriciate. THE SEASONS ALLMOST OVER GAARRRRRRR!!!

 

[Mi duckdown]

Re: Gearbox seal HELP!!!

really need to do a pressure and vacuum test on the lowerend to see where the leak is. it could be as simple that the drain and vent screws gasket washers are bad.??? One step at a time

 

[Chris1956]

Re: Gearbox seal HELP!!!

Agreed. It could be the driveshaft seal or shiftshaft seal leaking as well, or some combo....

 

[Druther]

Re: Gearbox seal HELP!!!

Thanks guys! But I know about the pressure tests and the three seals. I believe it is the seal behind the prop. What I need to know is how to replace threw bugger.

Any info is really appreciated.

 

[Druther]

Re: Gearbox seal HELP!!!

oh ya, I replaced the drain screws but good info

 

[carholme]

Re: Gearbox seal HELP!!!

Are you sure that is an 85 hp as the s/n comes up as:

MERCURY - ( 80 H.P. (1978 ))
Serial No: 04835879 Model No: 1080528

Parts List for model 1080528:

MERC 80 - Mercury, Mercruiser, Force, etc. Parts Lookup

Here is a link to the condensed version of the Clymer manual. Download it soonest to your computer as the link is short lived.

Small Engine Repair Reference Center Home: MERCURY - MERCURY FOUR-CYLINDER MODELS (1969-1989).

Gerry