JDF1986,

What weight oil are you using in your oil bath ar cleaner?
What year is you engine?

The 216/235/261 engines' oil bath air cleaners are supposed to have 50 wt oil. Lighter oil might more easily migrate up and into the carburetor (requiring more frequent addition of oil).

The owners' manuals indicate no set time period between checking the oil bath fluid level and also do not indicate the amount that might have to be added (manuals state interval and amount "As Required""). I have never had an oil bath filter "dry out" if I check it at every oil change.