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Sooty Oil From Propeller Hub

tboltmike

tboltmike

Regular Contributor
"My 75, 115 is leaking a carbo

"My 75, 115 is leaking a carbon black colored oil from the propeller exhaust. I had just resealed the drive shaft and shift rod a few months ago after finding emulsified water oil in the lower unit. Also installed a new water pump assembly. the oil was changed multiple times before and after the reseal to purge the wet oil.
After reassembly, I gave it a heavy dose of SeaFoam in the gas and ran on the hose in three 15 minute cycles of running and resting. Then Ike came and I hadn't fooled with it in a month. Yesterday I checked the oil level and it was about 3 oz low. I ran it on the hose for about 10 minutes with the fresh gas and oil no SeaFoam. I noticed a sheen on the water on the drive, but feeling the water outlets didn't give a clue. Today I checked it and it was 3oz low again and and about a tablespoon of black oil had run out of the exhaust. It is not coming from the aft prop shaft seal and looks to be coming from down the sides of the exhaust trunk, but the fwd end of the carrier is oily too.
Any ideas where it may be coming from and do I need to pull the lower unit and check the drive and shift seals? Can the carrier O-ring be changed without dropping out the lower unit?
Thanks, Mike"
 
What does a pressure test of t

What does a pressure test of the lower unit show.Trouble shooting and testing beats guess work every time.
 
"The color of the substance sh

"The color of the substance should be a dead giveaway. If the actual gearlube is not "black", then the leakage that you describe is simply the excess unburnt fuel mixture draining down thru the long sooty exhaust housing. A common occurrence with many engines.

As ikia suggests, a pressure check of the lower unit is in order for your peace of mind. Drain the gearcase, save the gearlube if it looks okay, then apply 7 to 12 psi of air to one of the drain/oil lever screw holes. If leakage exists, it will be obvious via sound or/and sight."
 
"Joe and ikia, thanks.
After

"Joe and ikia, thanks.
After 24 hours, there was about a 6 inch puddle under the skeg and had stopped draining. I pulled the top plug on the case and clean lube oozed out. So it must be as you say, engine oil. It will be a few days before it can get the bayou test.
Thanks a million."
 
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