Need help with oil leak on 1987 Mercury 80hp 2stroke

[thormx11]

I noticed the oil was leaking from the water intake on the side of my motor, so I did some research and found a bad shift shaft seal would cause this. So I ordered a new seal and replaced it. I noticed the old seal looked to be perfect, no cracks or holes, but I replaced it anyway. The motor didnt leak for about 2 weeks, but after the second or third time on the water, after I got back home I noticed oil was starting to leak out again.

What else could cause this?

When I Take the bottom oil screw out, a fair amount of water will drain out before any oil begins to drain out.

 

[thormx11]

Re: Need help with oil leak on 1987 Mercury 80hp 2stroke

Bump

 

[chum1]

Re: Need help with oil leak on 1987 Mercury 80hp 2stroke

u might get lucky just replacing the filler screw seals with the new blue style, if that doesnt do it its probably in the waterpump to shaft area, you can pressurize the lower end to about 5 lbs or so and check with soapy water but will need the tools

 

[thormx11]

Re: Need help with oil leak on 1987 Mercury 80hp 2stroke

What is needed for a pressure check? We run a body/mechanical shop and have most tools for cars laying around, hopefully we have something that would work for a pressure check!

 

[Chris1956]

Re: Need help with oil leak on 1987 Mercury 80hp 2stroke

Thormx, A leaky drivesahft seal will cause that as well. Just replace the water pump base, gasket and Oring. Inspect the driveshaft where the seal rides and use some sandpaper to clean the whole driveshaft. Oil the driveshaft up to you do not tear the new seal.

 

[aussieflash]

Re: Need help with oil leak on 1987 Mercury 80hp 2stroke

Could be seal on water pump base more than likely if oil leaking out of intake vent.I would change that and fill and vent screw seals to see if that stops leak.If not it has to be the Prop shaft seal.

 

[thormx11]

Re: Need help with oil leak on 1987 Mercury 80hp 2stroke

Thanks for the replies, I will try and order some new seals for the water pump tonight. When I had the LU apart the first time, I inspected the impeller, but I guess I should have inspected the gaskets as well.

 

[Mi duckdown]

Re: Need help with oil leak on 1987 Mercury 80hp 2stroke

Did you change the impellar?

 

[thormx11]

Re: Need help with oil leak on 1987 Mercury 80hp 2stroke

No, I did not change the impeller, it was changed in early January by Bass Pro. And it was still in perfect shape, I had bought one but I guess I will save it for next spring.