ILENGINE
Lawn Royalty
The true reason for elimination of the drain plug has to do with type of equipment and more specifically self propelled mowers. Due to the design of the equipment decks you could no longer access the drain plug when the engines still had them. And that goes back to Toro self propel mowers from the 80's. Or even in some cases without were the only holes in the deck were the engine mounting holes and a hole for the crankshaft. No access hole for the drain plug that was there but unuseable.Hello ILENGINE,
The argument I have heard by many of the environmental purist is the drain plug was eliminated to keep the DIY types from simply draining the oil out on the ground.
Most of the equipment that vertical small push mower size engines are mounted on would require a side drain. And that was eliminated years before the bottom drain was. And later versions that still used the bottom drain had an extension pipe that ran from the bottom drain plug out the side of the housing with either another engine style drain plug or just a pipe cap.