Gear oil leak argh

[pyro225]

Hi all...

Ok so I'm repowering one of my ssv151s with an early 80s merc 50 blue band. I saw it running and it seemed fine but was told it needed a service/ could do with an impeller... So I bought it..

I then changed the impeller and lay the ob on its side for a day... Gear oil leaked out the water inlet :-( not cool.. So I forked out for a new impeller housing kit with new gaskets and washers, fitted it and left it on its side for a day... Tada no leaking oil.... I then left it for a week still nothing... Great.. So then I move it about a lot taking it on and off the boat to measure up and laying on its side a few times (maybe 5-6) I then notice leaking gear oil dropping down the on but it's coming from the weirdest place - no idea how it's there and do I need to worry? I don't know what it's called so there's a pic and I've circled where it leaks from? Help

 

[bobsquatch]

Not 100% sure but I Think those are exhaust bypass ports. The good news is that since you have a wet exhaust that could just be residual oil from the original problem because those ports don't open up until the thermostats are open after the engine warms up.

 

[GA_Boater]

Yes, those are the Idle relief ports and let the exhaust back pressure vent when the motor is idling in the water. Thermostats do not control the ports. They are always spitting water and some exhaust. So most likely the oil is unburned two stroke oil.

 

[Texasmark]

Agree with others. Going to say that it would be impossible to have gear oil up there without the engine running upside down and it would have to come from the drive shaft seal(s) under the water pump housing. Have no idea as to your operational usage, but every, say 50 hrs of operation, check your lower unit oil for color and amount. If using Quicksilver oil it will be blue black and there will be a little air space left at the top (the vent screw).......after you check it a couple of times, if it's ok then nothing to worry about in my 50 years of boating opinion.

80's is a long time ago but lot of things in play as to "do you or do you not" have a seal problem. The seal under the water pump housing is (usually) two each seals mounted back to back and neoprene or suitable rubber that has a tendency to resist aging like natural rubber and resists petroleum products. Reason for that positioning is to protect the LU lubricant from both oil pressure from the lower unit pushing oil out as it heats up and water pressure from the engine, environment trying to push water in, or being sucked in when the LU cools and creates a partial vacuum.

HTH,
Mark

 

[dannys2004glastron175mx]

jest do the smell test , if it smells like gear oil its gear oil . it has its own unique smell :yuck:

 

[pyro225]

its definately gear oil :/ any ideas?

 

[racerone]

Pressure test the gearcase.----That is how location of leaks is determined.