More L/U questions - oil & water

Moody Blue

Captain
Joined
May 24, 2004
Messages
3,136
Last fall when winterizing the motor found water in the L/U. This spring I replace all waterpump components as well as drive shaft seals and new fill & drain screws with washers. Manual states the oil capacity is 12.5 oz but I was only able to get about 10oz into it before it spilled out the vent hole. I filled it very slowly and spun the prop repeatedly to make sure no air was trapped in the gears. Now when I leave the motor tilted up about 45* I find oil leaking out of a small water drain hole at the front of the L/U adjacent to the shift shaft. I am assuming the shift shaft seal is leaking and oil is getting by it and leaking out. Am I correct in this assumption ? How else could this oil be leaking out ?
 

achris

More fish than mountain goat
Joined
May 19, 2004
Messages
27,468
Re: More L/U questions - oil & water

Sounds about right to me. Replacing that seal is no big deal. Just get the right tool and it's easy. The tool number is 91-31107 and it'll cost you a whole $18.15. The bushing is best replaced complete, it's also quite cheap. You didn't say what engine you have, but by the oil quantity I'm quessing 85-200 hp. It's the same tool for all.<br /><br />Chris..........
 

Moody Blue

Captain
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May 24, 2004
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Re: More L/U questions - oil & water

Thanks achris for the quick reply. Is the tool necessary ? Looked like the whole bushing screws in/out of the housing. Am I right ?<br /><br />The motor is a 1993 40hp Mariner. I guess it is not normal for oil to leak out ?
 

Scali

Petty Officer 1st Class
Joined
Dec 18, 2004
Messages
299
Re: More L/U questions - oil & water

Rod , to quickly add something my '94 40 never takes the 12 ounces either , I bet I dont even get 10 ounces in the LU..just changed mine yesterday. I have to do my seals as well, my oil gets a little milky, been swapping it out every 10 trips, I trailer my boat no biggie.<br /> :rolleyes:
 

Moody Blue

Captain
Joined
May 24, 2004
Messages
3,136
Re: More L/U questions - oil & water

Thanks Scali for that info. Thought maybe I was doing something wrong. I'll look into the cost of the **** shaft seal and decide whether its worth the trouble or just do as you are doing. Guess I should have done all the seals when I had the L/U off the first time. Does this fall into the Stupid Human Tricks category ?
 

Moody Blue

Captain
Joined
May 24, 2004
Messages
3,136
Re: More L/U questions - oil & water

Hey what happened to s h i f t ? OOOOps look like I may have typed sh*t :eek:
 

Scali

Petty Officer 1st Class
Joined
Dec 18, 2004
Messages
299
Re: More L/U questions - oil & water

I did the same thing meaning I changed my impeller this winter, & forgot I was getting some water intrusion..<br />The deal with buying time with the seal replacemrnt job is make sure you use Marine gear lube not the auto stuff, this may be obvious but important because the marine lube has emulsiphiers in it that absorb the water making the lube still effective..<br />A friend of mine kept an older Merc going on his crab boat this way for years, bought the cheapest marine gear lube available & he never lost the lower unit.<br />I do hope to get to mine pretty soon though, sometime this decade..LOL
 
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