Gear oil leak from vent plug?

[JGL64]

While checking on my boat today, I noticed an accumulation of what appears to be gear oil on the cavitation plate along the side just under the vent plug and running back to the prop. I have a 2002 70HP Yamaha; I changed the gear oil including the fill and vent plug gaskets in the fall. Vent plug is tight; anyone have any suggestions of what may be the cause of the leak. Anything I should be looking for?

 

[rodbolt]

Re: Gear oil leak from vent plug?

hello<br /> remove the vent plug and check the gasket<br />]

 

[JGL64]

Re: Gear oil leak from vent plug?

Rodbolt thanks for the reply. Based on finding the leak, I am planning on draining and refilling in the Spring. I will be sure to change the gaskets again, I was wondering if I should look for any other causes.

 

[bigbrownbuku]

Re: Gear oil leak from vent plug?

sometimes the vent plug gaskets will split laterally if they are tightened too much. this cause them to spread out the edges of the plug.

 

[Triton II]

Re: Gear oil leak from vent plug?

Yes, I agree with BenC because I managed to split the lower plug gasket on my FT60B and didn't notice... got water (just a little) in the oil. It's worth changing the gaskets at each service... I now use a tiny dab of marine silicone to help seal the plugs without overtightening.

 

[JGL64]

Re: Gear oil leak from vent plug?

Pulled the vent plug today. Found a small piece of old gasket stuck behind the new one. Would it be reasonable to assume changes in temperature while the boat has been stored on the trailer would cause gear oil to leak past the vent plug if the gasket was not seated? Winter temps. have ranged for 3 deg. F to 47 deg. F in a two week period.

 

[rodbolt]

Re: Gear oil leak from vent plug?

yep<br /> if filled cold and allowed to sit in the sun, if the gasket is comprimised, it will leak.<br /> pay closer attention at maint time. ya got lucky <br /> most dont find a comprimised gasket until its a rust induced failure

 

[DJ]

Re: Gear oil leak from vent plug?

I've been following this. Is the vent screw above the cav. plate on that model?

 

[JGL64]

Re: Gear oil leak from vent plug?

yes....just above the plate

 

[DJ]

Re: Gear oil leak from vent plug?

Thanks for the clarification.