Tohatsu MFS6BS Lower Unit Leaking Gear Oil

MRA346

Recruit
Joined
Oct 9, 2018
Messages
2
I transported the engine laying down (Tiller handle down) in the back of my SUV while moving my boat to the coast (about a 3 hour drive). When I arrived and mounted the outboard on the boat, I noticed some gear oil had leaked out of the lower unit. It appeared to be coming out of the prop area but at this point I'm not 100% certain of that. I have not noticed a leak previously to this. How concerned should I be about this?
 

pvanv

Admiral
Joined
Apr 20, 2008
Messages
6,500
What makes you believe it is gear oil? Check the gear oil level, and check the crankcase level.
 

MRA346

Recruit
Joined
Oct 9, 2018
Messages
2
I smelled the oil and it smelled like gear oil. Unfortunately I can't get to the outboard until after next weekend. I should have brought it home with me but I was rushed for time when I left it.
 
Last edited:

km1125

Chief Petty Officer
Joined
Aug 10, 2016
Messages
496
Before you go too far, make sure it is gear lube. I could just be contaminated oil that's finding its way down the exhaust tube.

One of my engines (similar model) had a dripping of gear lube and I saw a piece of fishing line behind the prop that had found it's way under the shaft seal. I pulled it out and thought I had to replace the seal, but when I pressure tested the housing, it checked out AOK. Filled with fluid and didn't have any more leak.
 
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