Oil from speedometer holes on Yamaha lower unit

[99yam40]

How does oil/gas residue seem to be getting into the pickup for the speedometer on the lower unit of my 1999 Yamaha 40HP model #C40TLRX.
It does not always seem to be there but I have noticed it several times oozing out of the holes on both sides and running down the skeg of the lower unit while sitting on the trailer a day or two after running. At first I thought that it was a lower unit seal leaking, but it turned out to be a 2-cycle oil residue with that gas smell. The tube is not hooked to anything, just capped off. Has anyone else out there seen this before and is there a explanation on how it happens?

 

[Silvertip]

Re: Oil from speedometer holes on Yamaha lower unit

I think there is a simple answer to this. The holes you are looking at are not speedometer pickup holes. Some are mid section drains and others are water pickup ports for the water pump.

 

[bankerjohn]

Re: Oil from speedometer holes on Yamaha lower unit

FYI ... here's a picture of the speedometer pickup hole:

 

[99yam40]

Re: Oil from speedometer holes on Yamaha lower unit

I had to go out and look at the lower unit and you are correct. I would not have noticed the small hole in the frount,but there it was.

 

[99yam40]

Re: Oil from speedometer holes on Yamaha lower unit

I think there is a simple answer to this. The holes you are looking at are not speedometer pickup holes. Some are mid section drains and others are water pickup ports for the water pump.

So, I guess the oil I am seeing is just unburned fuel coming out of the mid section drains.
My thoughts are that running the motor on muffs while flushing the saltwater out just does not get the motor up to high enough of a temp. to burn all of the fuel.

Anybody have any other thoughts or input ?

2/12/201

I had to change the main jets to eliminate the high speed miss, because someone before me decided to drill out the old ones to get more fuel into the motor.Too much fuel will not burn properly and will cause the excess unburned fuel to run out somewhere eventually

I hope this will help others as they do searches for problems they are having.When ever you buy used equipment you can never rule out anything as you troubleshoot because you never know what others have done.