This is what I use ............See pictures
I set the bucket up on deck
with a hose running in it. Down below I have a T-fitting that the hose goes into.
I run the motor
until warm. Shut off the supply hose to the bucket and just as it's sucking the last couple gallons out of the bucket, I pour in some old antifreeze from last year (that has sat and settled out the particals).
Oh yeah! I forgot to mention I also use this to flush out salt
water if it's going to be sitting w/o use of the motor
for a while.