Tohatsu 3.5- oil leak on leg

[Kelpie]

My usually very reliable Tohatsu 2st 3.5 has a bit of a problem. I noticed some dark oil seeping from under the round plastic bung that hides the gear change connection, at the bottom of the leg. I know that the leg itself should only have sea water inside so I think perhaps a seal has gone on the top of the gearbox.

Is this a common problem? Is it a difficult one to fix? Should I get the gearbox off ASAP just in case water managed to get inside?

TIA

 

[Rigger Mortice]

Are you sure that it's not a bit of oil from the exhaust? If the oil that you're worried about is not the same colour as your gearbox oil then it's probably not gearbox oil.

There's no need to take the gearbox off to check it. Drain off a little oil and check that. If it's Ok then odds are you have no problem. Just top it up and use the engine. If you want to be belt and braces about it check it again after the engine has been used a few times.
If the oil is milky, you've probably got a problem somewhere.

Personally, I would check the gearbox oil. If it's not obviously wrong then I would clean the guilty oil up, use the engine a bit then have another look.

 

[Kelpie]

Here's hoping it is just exhaust oil.
The engine was last run in a barrel of fresh water- would this have any effect on anything?

I know I need to change the gbox oil soon but I don't have any and it's a Sunday and I was half wanting to use the engine today...

 

[VicS]

As suggested almost certainly partly burnt oil from the fuel mix and perfectly normal to see with a two stroke.

If its black, and smells burnt or of gasoline that is what it is


You'd not expect oil leaking from the gear case to be black, it would not smell burnt but rather have the unmistakable and characteristic " rotting cabbage" smell of EP gear oil!

You not be likely to get gear oil escaping from that plug anyway


More on the subject at http://forums.iboats.com/showthread.php?t=207285


However do check your gearcase oil for signs of water ingress. It should be "clear and bright" in appearance. Any milkiness indicates the presence of water.