mercury 70hp oil leak

[csootsman]

Hello, I am new to the forums. A friend directed me here.

My question is I have a 87 I believe, 70hp mercury outboard. I just recently purchased it used. The motor runs great, however the other day I noticed that when I had the motor trimmed in the trailering position I noticed a small amount of what I believe to be gear oil seeping out of the water intake holes.

I have drained the gear oil and it was milky and I also noticed that I was missing a seal in the gearcase drain plug. I will be replacing the seals on the drain and vent plug, however the oil leaking from the water intake concerns me. What gasket and or seal would I most likely need to replace.

Thank you for your time

Clair Sootsman

 

[tashasdaddy]

Re: mercury 70hp oil leak

the oil may be normal. http://forums.iboats.com/showthread.php?t=207285. you are on the right track to renew the plug seal, and refill, then check it after a couple of runs. those seals are the #1 place for water intrusion. if you have water next time, you need to pressure check the lower, and find where it is leaking.

 

[csootsman]

Re: mercury 70hp oil leak

Ok, I replaced the drain plug gaskets. But I am still getting a small amount of water from somewhere. I just ordered a service manuel for this outboard. I am thinking that I need to replace some seals?. Also the gearcase looks fine , no cracks. I also pulled the prop and found no fishing line.

I am pretty handy with a wrench, does this sound like something I could do. Also before I start doe I need any special tools? Thanks

ps the ser#0B274515

 

[Chris1956]

Re: mercury 70hp oil leak

If gear oil is leaking from the water intakes, it is likely the waterpump base gasket, seals or oring is leaking. it is a fairly simple fix. You drop the lower unit, remove the cover of the water pump, remove the impeller, pry up the waterpump base and install a new base which has the new driveshaft seal installed in it, with a new gasket and oring. Now install a new stainless wearplate and it's two gaskets and a new impeller. Reeassemble the waterpump and reinstall the lower unit.

when you manual arrives, read the procedure, buy the parts and have at it.

 

[csootsman]

Re: mercury 70hp oil leak

Thank you Chris, Now if I can go to the well one more time. Any suggestions to where I could get these parts online.

Clair

 

[Chris1956]

Re: mercury 70hp oil leak

Clair, Those parts are pretty common. Sierra, Merc and probably GLM make them. Try this site, try ebasicpower.com, try West Marine and Boaters World

A local Merc dealer is a good place since the cost will be pretty close to mailorder, but you will get the correct parts. Sometimes ordering the waterpump base is a challenge. You should inspect the upper waterpump housing for cracks and wear. Replace it is necessary.

 

[csootsman]

Re: mercury 70hp oil leak

Thanks