My model 38527 push mower has a drain plug at the bottom of the engine. If however there is an accumulation of dirt you might not see it. It takes a square socket rachet inserted into the plug to remove it. My mower is one year old. The other suggestions abaout tipping the mower over and draining through the oil imput on top of the engine applies to some models. I hope this helps.
evans
March 2009