1967 Johnson 40hp Electric Shift LU Problem

[Uriah]

Hey everyone, Ive been having a problem with my lower unit oil coming out totally white after one run. Ive drained it into a bottle and tried to see how much water would separate. After 4 days of the bottle sitting, no water has separated. Does this mean a very minute amount of water is entering? Ive been changing my LU oil every time i take the boat out. There is no local dealer to get type C oil for the gearcase, so i have been using 30w motor oil. The shop manual says you can use 30w in emergency use. So my two questions are; how serious of a water problem does it sound like i have? and two; will 30w destroy my LU after prolonged use? Thank you very much.

 

[freddyray21]

Re: 1967 Johnson 40hp Electric Shift LU Problem

it does not take a lot of water for it to turn milky, but you would think it would separate after sitting. Don't know about the 30wt, but if the shop manual says 30wt in an emergency I would not continue to run it with it all the time.

 

[Uriah]

Re: 1967 Johnson 40hp Electric Shift LU Problem

thanks freddy for the advice. I did a test this evening, i put a few ounces of oil in an empty water bottle, then added a very small amount of water. Within minutes, you could clearly see the water starting to separate. So, im thinking (and hoping), its just a very tiny amount of water causing this. Any other suggestions anyone?

 

[R.Johnson]

Re: 1967 Johnson 40hp Electric Shift LU Problem

Those gearcase's had two stud's that held the lower gearcase to the upper. Those two stud's had a metallic washer that acted as a seal where they screwed into the lower, much like a spark plug washer. Those stud's must be drawn up tight into the lower, or a leak can result. also use sealer under the upper washers for these stud's. Gear lube has a higher, high pressure rating than motor oil. Motor oil would cause gear over heating as it would break down under the pressure's encountered. I would not exspect to get by using it for long. Pressure test the unit to find the leak, as it could be several places on that gearcase.