Pressure tested lower unit leaking water

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tom24

Seaman Apprentice
Joined
Feb 26, 2004
Messages
33
Hi,<br />I just rebuilt a lower unit on a 1984 50 hp Johnson. Pressure tested it to around 13 pounds and held pressure with no leaks for at least 4 hours .I ran the motor for around a half hour and found the lower unit oil full of water.How can so much water enter the unit a less than a half hours time? Thanks for your help,Tom
 
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rwise

Captain
Joined
Jul 5, 2001
Messages
3,205
Re: Pressure tested lower unit leaking water

tom<br />I had a lower unit "rebuilt" passed presure and vacume tests. Hit the water with it and had the same thing. Pulled it down myself and found the bearing wer out, enuf play in them to let the seal leak, new bearing and no more water in side! may not be whats up with yours, but there it is.<br />Richard
 
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Paul Moir

Admiral
Joined
Nov 5, 2002
Messages
6,847
Re: Pressure tested lower unit leaking water

Just one idea - check to make sure both your driveshaft and propshaft are straight. If they're bent, they'll leak when spinning but sometimes not while stopped. Did you experience any vibration when running?<br />Can you perform a vaccum test?
 
OBJ

OBJ

Supreme Mariner
Joined
Dec 27, 2002
Messages
10,161
Re: Pressure tested lower unit leaking water

In addition to the above good advise, here's a short "think about it" list.<br /><br />Seals installed back-to-back.<br />Prop shaft not grooved where seals make contact.<br />Drive shaft not grooved where seals make contact.<br />New washers on drain and vent plug.<br />Bearing carrier O-ring seat is not dirty or deeply scrached.<br />Bearing carrier seated all the way in.<br />Shift shaft O-ring seated in bushing groove.<br /><br />As Paul suggested, a vaccum test is just as important as a press. test.
 
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R.Johnson

Rear Admiral
Joined
Sep 24, 2003
Messages
4,446
Re: Pressure tested lower unit leaking water

Also, check the seal, and bearing surface on both the prop. and drive shaft. If the drive shaft shows a lot of wear, you could have a sprung gearcase. That drive shaft has a lot of spring to it. It would take a lot of bending to give it a permanent bend
 
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