Yanmar 4BY2 180 HP Oil Filler Cap

[JESnyder1234]

I am getting ready to change the oil in our Yanmar 4BY2 180 HP engine for the first time since we purchased the boat. The oil Filler cap is surrounded by a rubber sleeve, for a better explanation, the cap itself doesn't seem to budge no matter how hard I have tried to open/turn it. Does it take a tool to open it or just brute strength?

 

[Brian B]

If I understand your question correctly the rubber boot under the oil fill cap connects to a plastic tube. The tube would direct spilled oil to the bilge. The fill cap itself is similar to a radiator cap in how it is removed and and tightened. It should release with about a 1/4 turn counter clockwise. There is a rubber gasket under it so if it hasn’t been off in a while it may need some persuasion. Have you changed the oil filter? That may be a challenge first time around. Ask for some tips if you haven’t done it. There are a lot of older posts on here regarding the filter.

 

[JESnyder1234]

Thanks, I will try a little harder to turn the cap.