1979 9.9 Leaking oil after running

[gliderflyer]

I've recently purchased a 1979 9.9 Johnson. I've run it twice in salt water and after flushing with muffs and putting away in my shop there is very dark thick oil leaking from around and inside the prop. I'd guess about a tablespoon or a little more each time. It has a gas smell to it as well. Does this sound normal?

Thanks!
Randy

 

[relstabw]

Re: 1979 9.9 Leaking oil after running

Yes. It's a byproduct of the exhaust. My dealer had a name for it but I don't remember what it is right now. I noticed the same thing and was also concerened. My old Johnson 40HP was black and my 70HP is painted white so I notice everything I didn't notice on the old motor.

 

[kenmyfam]

Re: 1979 9.9 Leaking oil after running

Unburnt 2 stroke oil most likely.
Welcome to iboats.

 

[Vic.S]

Re: 1979 9.9 Leaking oil after running

Black or dark oil ... partly burnt oil from the fuel .. draining out is normal but it is not "thick" and a tablespoon full sounds rather a lot.

I would check the gear case oil for level and signs of water ingress as a precaution and peace of mind.

Read OIL LEAKING AROUND LOWER UNIT

 

[jay mendoza]

Re: 1979 9.9 Leaking oil after running

I have that too, if it's black and smells like fuel, it's just 2-stroke oil from the exhaust. As the engine gets older, and the rings gum up in the grooves, it will get worse, and your fuel consumption will increase. Using OMC engine tune-up, Valv-Tect marine motor de-carb, or Sea Foam decarbonisation treatments will reduce this and increase the compression.

Order a couple new drain plug washers and some gearcase oil, drain the gearcase and then you'll know if it's OK.

 

[gliderflyer]

Re: 1979 9.9 Leaking oil after running

Great advice from all of you, thanks!

I checked my lower unit lube level and I think it has gone down a bit. I'm thinking it may be a combination of exhaust residue and gear lube leaking as it is very thick like gear oil but definitely smells of gas as well. I need to drop the lower unit anyway to replace the water pump just for good measure. I'll replace the seals while I'm there. Hopefully I don't find salt water in there.

Thanks!
Randy