I just changed the oil and filter on a 17 HP Kohler engine on a Craftsman tractor. The adapter the filter threads onto has a tiny hole of about 1/8 inch diameter. Does this tiny hole flow all the oil the engine needs, or, is this some kind of bypass filter that filters a small portion of the oil? Thanks in advance for any advice. The mower runs fine, I was just curious how the oiling system worked.