:Milky" lower unit oil

[Frank Acampora]

For those who are wondering if their lower unit oil is contaminated with water, I submit these photos. This occurred with only about five minutes run time. I was water testing an engine I had sold and mounted on a boat. It did not perform satisfactory so I brought it back to the garage. There I observed white oil dripping from the water intakes.

The lower unit is a dual exhaust, 2 piece drive shaft, off a 1990 90 HP Force. Upon removing the water pump and bottom plate, I discovered that the top seal had failed AND the lower seal had worked out of the plate, sealing absolutely nothing. Two new seals and a bit of Permatex to lock them in place solved the problem.

 

[tpenfield]

Re: :Milky" lower unit oil

Looks more like the water is contaminated with oil . . .

 

[MickLovin]

Re: :Milky" lower unit oil

Been there done that one Frank

 

[jerryjerry05]

Re: :Milky" lower unit oil

My 88/85's both leak water into the oil.
The drain plug leaks no mater what I do.
They're the allen head set screw and I use thread tape and I've used plumbers putty and they still leak a bit of water into the oil.
But I change my oil 3-4 time a year because I know they will leak.

 

[jerryjerry05]

Re: :Milky" lower unit oil

My 88/85's both leak water into the oil.
The drain plug leaks no mater what I do.
They're the allen head set screw and I use thread tape and I've used plumbers putty and they still leak a bit of water into the oil.
But I change my oil 3-4 time a year because I know they will leak.

 

[tater76]

Re: :Milky" lower unit oil

@jerry, my 89/85 does this too! I check it after every 2 outings or so, and replace as needed. I pressure tested it after a complete reseal, and the drain plug just would not quit bubbling. Mind you it is not a massive leak, just enough to pull a teaspoon of water in per every 5 outings, or 10-15hrs of run time. I tried what you did with the same results, and after exhausting my patience, I just resigned to be diligent about checking and changing the oil. It has been running this way for the past 2 years without issue.

 

[Frank Acampora]

Re: :Milky" lower unit oil

So tap the drain plug hole for 3/8 X16 and spotface it with a counterbore. Actually, drill and spotface then tap it. Then use the standard drain plug with gasket--problem solved. But, unless you have a friend with one, the counterbore will be expensive to buy. It is not a standard Sears tool.

Chrysler/Force use three different drain plugs: the standard 3/8 plug, the 1/8 NPT plug just like the one in the head, and the small 5/16 socket head set screw, so there is plenty of meat to enlarge the drain hole.

You can also buy a 1/8 NPT tap for about 16 bucks and buy a bronze or stainless plug. Because they are tapered, you must not tap too deeply but they will seal just like black iron pipe and fittings.

 

[tater76]

Re: :Milky" lower unit oil

I have contemplated going that route, but as you stated, the tools are expensive. I have the flathead plug, I believe it is the 3/8 if I remember correctly. I installed the gasket on the plug included in the rebuild kit, and it immediately leaked. Then I tried a nylon washer, then back to a fiber washer just thicker, and finally thread tape as a last ditch effort. When I originally purchased the motor the drain plug was nearly impossible to remove. It wasn't corroded in place or anything, it was just super tight, and the screwdriver slot was worn. Maybe the sealing surfaces were warped from over tightening/removal? Anyway, If I get tired of fitting the bill for gear lube I will definitely look at fixing it correctly. Thanks for the info Frank