Lower unit seal

[Masonk3859]

I recently bought a 90’ 30 horse Johnson off a guy I know for 150$. The outboards didn’t run but it’s was not in terrible shape, and had good compression so I figured I’d fiddle with it a little bit. Today I drained the lower unit oil and noticed some water in my oil. It wasn’t terrible yet I know that it is because of a problem. I ran a vacuum test today and was holding 10 pounds of pressure for an hour. When I took off my prop, I noticed the prop shaft had fishing line on it and a “machined cylinder” for lack of a better name was floating loosely on the prop shaft. I’ll attach some pictures below. Could this be the cause of my water leak? I’m holding 10 pounds of pressure for long periods of time so I am overall a tad bit confused. Also, is this cylinder supposed to be fitted into the slot on the prop shaft? I’ll attach some pictures below any help is appreciated. Thanks in advance! If you have any questions about it feel free to ask

 

[clemsonfor]

I believe that's your thrust washer. If your holding 10 pounds , that's a lot, I don't think your leaking. The fishing line could of got between the shaft and seal at one point and let the water in or maybe it could just be moisture from condensation in a small void for a long time? If it wasn't milky and just a few drops I wouldn't worry about it. It will hold that water in suspension and not matter. Also there is a void in the bottom that's in the aluminum housing that a little water can settle in and not touch any steel. If it was me I would get it running and worry about the small possibility of the lower unit on down the road. Holding ten pounds for a long period is good.

 

[Masonk3859]

I believe that's your thrust washer. If your holding 10 pounds , that's a lot, I don't think your leaking. The fishing line could of got between the shaft and seal at one point and let the water in or maybe it could just be moisture from condensation in a small void for a long time? If it wasn't milky and just a few drops I wouldn't worry about it. It will hold that water in suspension and not matter. Also there is a void in the bottom that's in the aluminum housing that a little water can settle in and not touch any steel. If it was me I would get it running and worry about the small possibility of the lower unit on down the road. Holding ten pounds for a long period is good.

. So that is a thrust washer and apart of my lower unit seal you think? Am I supposed to seat that down in the lip?

 

[clemsonfor]

Did a thrust washer come off behind the prop? There usually is one back there. Without looking at the parts breakdown I can't say for sure what it is cause I don't know. It also could be a seal retainer or just something to protect the seal there.

Now you have me wondering I'll look it up.

 

[clemsonfor]

Ok I just looked at your diagram, yes that is your thrust washer/bushing as it calls it. It should just be on the prop shaft behind the propeller

 

[Masonk3859]

Ok I just looked at your diagram, yes that is your thrust washer/bushing as it calls it. It should just be on the prop shaft behind the propeller

Thanks a lot For what it’s worth the oil in the lower unit was jet black. The water came out first and then the oil came next. Not sure what that means exactly but I guess your right to say if I’m holding pressure I should be alright. Left it pressurized tonight hopefully in the morning it looks alright!

 

[jimmbo]

Don't forget to replace the Gaskets on the Drain and Vent Screws. They have been known to let a few Drops of Water get in.