Yamaha 90Hp 2-stroke oil leaking from bottom carb

[chrisd1972]

I have a 2007 model yamaha 90hp 2 stroke motor.

I have noticed that it is leaking 2 stroke oil. On closer inspection, it seems like the oil is leaking out of the bottom carb.

I took off the air filter and the inside of the air filter has about 20ml oil lying there and also the inside of the carb has quite a bit of oil.

What would be causing this?

[robert graham]

It's normal...the gas evaporates and leaves the oil....my C90 motor always has oil sitting in the bottom of black plastic air silencer and mouths of carbs...

[rodbolt17]

could be about normal.
could also be a leaking oil line check valve.

[chrisd1972]

I don't think it is normal, it is leaking a lot, then running out the bottom of the engine housing down the outside if leg.

Seems to be leaking more if the motor is tilted down.

Where is the oil line check valve? How do I check that?

[rodbolt17]

seeing how it is an oil line check valve one could assume it is in the oil line.
there are 3.
you test them with a mity-vac or similar tool and a service manual.

[Jason2tpa]

I don't think it is normal, it is leaking a lot, then running out the bottom of the engine housing down the outside if leg.

Seems to be leaking more if the motor is tilted down.

Where is the oil line check valve? How do I check that?

Check valves #13.

[simpleone]

I have a 1985 115 that was doing the same thing. I just got it to stop leaking and am going to test run it as soon as I get a chance. I took the top cover off of the oil injection pump and sprayed brake cleaner through the check valves from the pump side of the cover (up from the bottom in the direction of oil flow). Nothing will spray through the other way. It stopped leaking but like I said I have to run it still. It should be okay, oil ran out whether the engine was running or not, lots of it. it was coming from a little brass button on the bottom of the carburetor venturi. I have a thread on this site with a picture of it. Anyway, that is what worked for me. Hope you get it fixed.