Merc 850 Oil Leak

[Yammerhead]

I have a 1973 Mercury 850 that has a leak. I haven't had it in the water yet. The oil is coming from a vent hole half way up the leg. Where would be coming from? Is there a vent or overflow (wishful thinking) or is there a seal that is toast?

Pic...

 

[Intuition Gloucester]

Re: Merc 850 Oil Leak

I had a cracked cap on the oil resevoir that was causing an oil leak. Once the thing totally gave way it was a mess with oil leaking all over the place while under way. A new cap and I was back in business.

 

[Chris1956]

Re: Merc 850 Oil Leak

Your waterpump has some seals and gaskets for the gearcase that are leaking badly. You need to drop the lower unit and replace the leaking seals and gaskets. If you have not put in a new impeller in a couple of years, this is the time.

The only seal that does not come with the impeller repair kit is the driveshaft seal. You need to buy a new waterpump base to get this seal. You should be able to buy a combo kit with the impeller and waterpump base.

 

[Yammerhead]

Re: Merc 850 Oil Leak

Thanks for the replies. I figured it mean't I would have to tear into the leg. Hopefully it's just the seals and nothing else. Whoo! Hoo! Another project... Looks like it's time to buy the service manual.