Honda 10hp Gear Oil issue

[Neil Jardine]

Hi there,

I have recently purchased a fishing boat with a 10hp 2012 Honda as the main engine


A few days after I brought it out the water I noticed oil was leaking from the prop shaft area, dripping down the skeg. The oil was blue in colour, with no signs of water. Until then there had not been any oil leakage from what I noticed.

I decided to drain the gear oil anyway, I unscrewed the lower plug (the fill one?) without loosening the upper one, when I freed the screw there was a huge amount of pressure built up and the oil shot out. Is this normal?

My question is what could be causing the leak around the prop area? Is it related to the pressure build up? Like I said there was no sign of any water in the gear oil. I took off the prop but could not get the prop shaft housing off, it seems stuck to the lower unit.

Any help greatly appreciated. And if anyone needs more info let me know.

 

[jduck1]

Sounds like the person before you might have overfilled the gear case? Not sure about the newer motors but on my 80's 10HP I laid the motor on its side and filled the gear case putting too much oil in above the top screw. I think it created too much pressure and pushed oil out of the impeller shaft seal. Found it as excess oil made its way from the impeller housing, into a drain port, and showed a small puddle on the garage floor. At first I thought it was a motor oil issue but after pulling the lower unit off to see what was going on I found the issue in the impeller seal area. In my case I had oil leave and water get in so I drained and refilled with the motor upright and using the bottom hole to fill until it overflowed from the top hole. All is well now.