Changed the lower unit lube in my 95 merc 100 hp and it started a slow drip around the drain hole. Always use a new gasket but it kept leaking. Drained again cleaned up the seat area another new seal and put it back together,still leaking 
Finally covered screw with silicone and seems to stop leaking. Any suggestions??
Gundy
How much did it leak? A few drops? A tablespoon? A cup?
Did you leave the top plug out when you pumped in the fresh lube through the bottom plug?
Grouse
Yes, Both top plugs were out. I have had trouble with this in the past as I don’t have a very good seal area. thought about trying a copper compression seal. Thanks
Gundy
Is it possible your threads are stripped and not sealing tightly?
Try 2 seals stacked on top of each other. That would give you more gasket compression. OMC also used to make nylon lower unit gaskets.
Are you tightening the screw with a regular screwdriver? A screwdriver attachment for a socket wrench has a lot more leverage, but don’t go wild and strip the threads!
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Try 2 seals stacked on top of each other. That would give you more gasket compression. OMC also used to make nylon lower unit gaskets.
Are you tightening the screw with a regular screwdriver? A screwdriver attachment for a socket wrench has a lot more leverage, but don’t go wild and strip the threads!
I am going to try that next. I don’t like the idea of stacking seals but if it works that will be great.
Gundy
Call Supreme Marine they are very helpful and know all things Merc
How much is this leaking and has it continued to leak beyond a day or so after the change?? It’s not just as simple as there being some lube that was clinging to the bottom of the skeg after draining the old lube, is it?
The lube in the lower unit is not under pressure like engine oil, so it shouldn’t take 6 bazillion foot pounds of torque to seal that little gasket. Something else is going on here if this is leaking consistently.
Grouse
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