Lower unit oil milky

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skiman12b

Recruit
Joined
Apr 5, 2011
Messages
5
Ok.....I installed the points, condensor and a impeller. I changed the oil in the lower unit and it was slightly milky. I went ahead and put new oil back in it and ran it in a barrrel for 3-4 minites and adjusted the carb. I did another check on the oil and it is very milky looking now. Could it be the driveshaft seal leaking? Its a 1968, 33ho Johnson and it has a split gearcase.
 
Mas

Mas

Lieutenant Commander
Joined
Oct 3, 2006
Messages
1,656
Re: Lower unit oil milky

It could be drive shaft seal, prop seal, shift rod seal, spaghetti seal, or drain/vent screws. Did you replace the nylon washers under the drain/vent plugs when you changed the lube? They should be replaced each time...start there.

Mas
 
S

skiman12b

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Apr 5, 2011
Messages
5
Re: Lower unit oil milky

I replaced the plugs and gaskets for starters. It still milky. I guess I will take the lower unit cover off and replace the seals. Does this require speciality tools or is it pretty straighforward?

Thanks..
 
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dwtata

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Feb 15, 2010
Messages
11
Re: Lower unit oil milky

I have had 'milky' looking lower unit oil before also. All my seals and everything were fine and I beleive it was 'milky' looking because the oil I had in previously was black, and the oil I replaced the black oil with was clear/yellow/gold. After a season of the residual black oil and gold oil mixing in the gear case it came out somewhat milky. It may be that, or it could be one or all the things Mas listed.
 
Mas

Mas

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Oct 3, 2006
Messages
1,656
Re: Lower unit oil milky

The gearcase is pretty straightforward. Use 3M 847 as a sealant. You may have to improvise something to get the shift rod bushing out.

Mas
 
S

skiman12b

Recruit
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Apr 5, 2011
Messages
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Re: Lower unit oil milky

Thanks for the information - very helpful. I just ordered the seal kit from the site.
 
B

boobie

Supreme Mariner
Joined
Nov 5, 2009
Messages
20,826
Re: Lower unit oil milky

Before you tear it down take it into a dlr and have it pressure tested. That takes the guess work out of where it's leaking.
 
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