70 HP mercury with brown discharge out prop

[Larson70]

Trying to figure out what gaskets to replace. The lower unit gear housing maintains a level of oil but the propeller slowly leaks out a light brown discharge which i am assuming is a mix of water and gear oil. What gaskets or O-rings or bushings separate the 2 and how easy are they to change.

 

[oldman570]

Re: 70 HP mercury with brown discharge out prop

What year is the motor? Is it LU grease or just burnt exhaust oil draining from the exhaust and motor. Is there water in the LU?

 

[Mi duckdown]

Re: 70 HP mercury with brown discharge out prop

^ Yes. check Lower end Lube for water.
.Serial number?
Pre 74 (I Think) mercs were not ss drive shafts, and that was a problem concerning water intrusion to LU.

 

[Larson70]

Re: 70 HP mercury with brown discharge out prop

its a 1989

 

[Larson70]

Re: 70 HP mercury with brown discharge out prop

theres no water in the lower unit...

 

[oldman570]

Re: 70 HP mercury with brown discharge out prop

If there is no water in the LU , then it is fine. If the oil injection pump has been disconected, and you mix a 50 to 1 fuel, what your seeing is burnt fuel from the motor idleing while loading the boat on the trailor or on muffs. Everything should be good to go have fun.
JMO Oldman570

 

[Chrisjl]

Re: 70 HP mercury with brown discharge out prop

i had the same problem with my 89' 45hp, i drained my lower unit and then refilled it and it was fine except when it first started tons of smoke but after about 10 minutes of running if went back to normal

 

[coolbri70]

Re: 70 HP mercury with brown discharge out prop

this is what i get when i run on muffsif this is what you are seeing, it is the 2 stroke oil from the fuel it is normal