Forum Discussion
azrving
Feb 19, 2015Explorer
Here is a picture of a Briggs and Stratton breather valve which is the same concept on most small engines. The large hole is the "reed" or one way valve disc. The small hole and those small slashed spots in the gasket are the oil return hole that lets any oil/mist oil drain back down into the crankcase. The larger hole at the top right edge mates up with a tube that runs over to the air filter housing. If that little hole was to become plugged, it may fill with oil and allow it to enter the pipe to the air filter.

On page 6-13 of this onan manual
they talk about the breather but dont mention the drain back hole or show it. It would be a small hole in the baffle plate.
One Onan breather style

On page 6-13 of this onan manual
they talk about the breather but dont mention the drain back hole or show it. It would be a small hole in the baffle plate.
One Onan breather style
About Technical Issues
Having RV issues? Connect with others who have been in your shoes.24,329 PostsLatest Activity: Oct 27, 2025