67 Johnson leaking oil from shift linkage cover

Markrine79

Recruit
Joined
Feb 9, 2013
Messages
1
HELP! Is there an upper gasket that is allowing all of this oil to leak from my lower unit? Just replaced the lower unit seals and the driveshaft o ring but its still leaking black oil. Also my spark plugs are really black and wet.
 

F_R

Supreme Mariner
Joined
Jul 7, 2006
Messages
28,195
Re: 67 Johnson leaking oil from shift linkage cover

The shift rod connector access plate leads to the exhaust chamber. There is exhaust in there. The oil that you put in the gas goes through the engine where some is burned and the rest goes out with the exhaust, where it picks up carbon particles and turns black. That is what you are seeing leaking out the cover. It is totally harmless and was heading to be discharged out the bottom with the exhaust anyway. If the mess bothers you, cut a gasket and put it behind the access plate.

That are is WAY above the gearcase and there is no way gear oil is leaking out way up there.

EDIT: Several reasons lead to wet, black plugs.

1. Carburetor adjusted too rich, sending more fuel to the cylinders than it can burn
2. Running at prolonged idle, not developing enough heat to burn the stuff off the plugs
3. Ruptured fuel pump diaphragm
4. Running it in a bucket or barrel.
5. Some wetness/oilyness is normal

Especially #1
 

kbait

Commander
Joined
Nov 13, 2007
Messages
2,445
Re: 67 Johnson leaking oil from shift linkage cover

And, wet/black plugs would be caused by incomplete combustion (poor compression or spark), or too-rich fuel-air mixture delivered from carb. Try leaning out the carb needle valves. You could also post hp for more precise advice.

Good luck
 
Top