Oil in Air Cleaner

How much oil is supposed to go in the oil-bath air filter of a TO 35?  July 20, 2016.

These oil bath air cleaners are used on tractors, and commercial engines from the 1930’s through the 1960’s. Servicing them is relatively simple, remove the oil cup, dump out the oil and residue, wash out the cup, and refill to the indicated line with fresh oil. As long as the oil is at the level of the line in the cup, the level is correct.