Small amount of water in gear oil...

[slowzuki]

Hey all,

I purchased a 1978 DT25 and took it out for the first time last fall. Before the maiden voyage, I changed the gear oil and a small amount of water came out before the oil. I would say about an 1/8 of a cup, maybe less. I went ahead and changed the oil and ran the boat for the day on the lake. When I came home I pulled the oil drain plug to see if any water had made its way in and sure enough, there was once again about an 1/8 cup of water in the gear oil. I called a few local boat shops and nobody will take a look at it because its older and parts are hard to find. One shop said that it could be my thermostat. Does that make sense to anyone? FYI, i pulled the thermostat and tested it in water above 62 celsius as it was marked on the thermostat. It seemed to open up just fine. Any suggestions?? I'm thinking maybe a pressure test? No oil leaks out anywhere.

[Moonlighter]

Water in gearbox oil has nothing to do with thermostats..... I would not let whichever mechanic suggested that anywhere near this engine.

Looks like you have a gearbox seal that is damaged and letting water in. Needs to be pressure tested and any outboard shop should be able to do that for you, its nothing special to do on that motor vis a vis any other.

In the blue line near the top of this forum is a link to “Buy Suzuki Parts”. If you click there you can then select your engine year and model and hp and see what parts are available.

[slowzuki]

Thanks for the info. I have a gauge and pump, so I’ll attempt the pressure test later this week. I’ll post my findings. I think you’re right about the mechanic that mentioned the thermostat. I didn’t think that made any sense at all.

[slowzuki]

I removed the gear case from the engine and found that my shift shaft seal is leaking. Would this be the culprit for the water getting in the oil? I wasn't aware that water entered into this part of the case, but i'm not knowledgeable with boat engines, just dirt bikes.

[tsturm]

A teaspoon or more is a leak, 2-3 drops that come out before the oil while draining is probably condensation, if you live in an area with wild temp/humidity swings.

[Solarman]

The shift shaft seal could easily cause the leak. As the gear case heats up during use, oil expands causing pressure, oil leaks out. As the unit cools down (at idle, or neutral), this creates a vaccuum, and because the lower unit is in the water it will pull water in. If the seal is bad, replace it.

Good luck, post back on what you find out.