Lower unit leaking but holding air

J

jrtredo

Seaman Apprentice
Joined
Apr 27, 2007
Messages
34
I have a '79 70 Evinrude that I'm getting water into the lower unit oil. It has been really milky the last two times I have drained it. I made a pressure tester and pressure tested the lower unit to 15 psi and it held that pressure for 30 mins. I also tested with vacuum and it held a vacuum for 30 mins. Has anyone else had this happen to them? The drain and fill plugs have new gaskets. I looked at the propshaft and when I'm looking at the seal I can see the spring that is supposed to keep the rubber tight to the shaft. Any ideas? Could that seal be letting water in or letting oil out when the prop is turning?propshaft.jpg
 
D

Daviet

Fleet Admiral
Joined
Sep 24, 2008
Messages
8,958
Re: Lower unit leaking but holding air

I usually rotate the propshaft, driveshaft and shift rod while under pressure/vacume, to see if there is any leakage at those points.
 
J

jrtredo

Seaman Apprentice
Joined
Apr 27, 2007
Messages
34
Re: Lower unit leaking but holding air

Next time I take it out and drain it I will try that. Should I be real concerned at this point? I put synthetic lube in for now to be safe.
 
W

wilde1j

Vice Admiral
Joined
Apr 15, 2002
Messages
5,964
Re: Lower unit leaking but holding air

Did you drain the gear oil before the test? As Daviet suggested, moving the shafts gives a more representative test. Any of the seals may leak if the shaft or bearings are worn.
 
J

jrtredo

Seaman Apprentice
Joined
Apr 27, 2007
Messages
34
Re: Lower unit leaking but holding air

Yes, I drained the oil before doing gthe test. I will try turning the prop next test.

thanks
 
B

boobie

Supreme Mariner
Joined
Nov 5, 2009
Messages
20,826
Re: Lower unit leaking but holding air

Do what Daviet said above and you will find the prob. Just turning the prop shaft alone is not enough.
 
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