LEAK FROM LOWER UNIT!!!!!

theck4291

Petty Officer 3rd Class
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Jul 19, 2015
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Was doing final preparations inside of the boat, getting it ready to launch(just completed restoration) and my 2 yr old son was in the boat with me... I had the outdrive up and locked down on the bar that helps keep the weight off of it(not sure what it is called) and my son pressed the lower button on the console and lowered down the outdrive even though it was already tight on that bar... I got out and noticed it was leaking oil from directly above where the bar was!!!! What happened, and how do I fix???? THANKS IN ADVANCE
 

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theck4291

Petty Officer 3rd Class
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Messages
87
Outdrive is a MC1, boat is a 1973 Fiberform cuddy voyager with a 1973 mercruiser 165 hp inline 6 engine
 

Bt Doctur

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what "bar" are you talking about. do you mean the flushing attachment on the lower unit. it needs to be removed before use
any oil leak needs to be fixed before using the boat,did you have the drive off for service and was it pressure tested before install?
 
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theck4291

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No, not the flushing attachment... it is the bar that props up the outrdrive to take some pressure off of it while trailering it.... when putting the outdrive back together does there need to be some kind of sealant on that nut?
 

Scott Danforth

Grumpy Vintage Moderator still playing with boats
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I think he is referring to a a motor-defloperizer. some people call them a transom saver.

usually not found on an I/O
 

Bt Doctur

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that nut is the forward mounting nut for the lower unit, nothing goes on it.
the drive really does not need any support during trailering and is kept in the full down position when not being used or trailered
 

theck4291

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Is there maybe an o ring I forgot to put back on the forward mounting nut? After looking at the oil mess on the ground, it's possible that it has been leaking for a few days. Do you know of or possibly have a diagram of how the lower unit goes back together in regards to o rings maybe I missed one?
 

Bt Doctur

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there is one small O ring between the units just to the right if the water pump housing. it must be there
 

Bt Doctur

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UntitledA11_zps8knxcil4.jpg
 

theck4291

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ok, I THINK i put that back in, but maybe I didnt... would that cause oil to leak out of that bolt? it is also possible that it was coming out of the shift cable-lever/thing..... and as it was running out could have looked like it was coming out of the bolt.... can you also please explain how the gear oil works, does it fill the entire cavity or where does it fill?? sorry and thanks!
 

theck4291

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just filled the outdrive back up with oil, and it doesnt seem to be leaking????!?! i think i am just going to play safe and take it apart and check for that O ring...
 

Bt Doctur

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Typically a mercruiser outdrive fills from the bottom plug until it comes out the top plug
 

Bt Doctur

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in my pic I posted oil can only leak from the shift shaft bushing or the missing O ring called a quad seal or from the water pump base seals
 

theck4291

Petty Officer 3rd Class
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IT IS DEFINITELY COMING FROM THE SHIFT SHAFT AREA... HOW DO I FIX THIS?
THANKS
 

theck4291

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thats exactly what i did, i filled it from the bottom til it came out of the top
 

wahlejim

Master Chief Petty Officer
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Jul 23, 2015
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You need to pressure test that outdrive. There are instructions in the adults only section at the top of the mercruiser forum. My guess is there is oil leaking from the drive shaft seal. It will run down and leak right where your picture is showing. Do the pressure test to confirm.
 
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