The drain hole in the center tube is only about 1/16" in diameter, and it's halfway up the tube to prevent the filter from draining completely and delaying oil pressure buildup when starting. Even if you remove the return line the canister won't drain. The suction gun is your friend! Some canisters did have a drain plug in the bottom, but not all of them.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!