But this new Mercury engine has no "blue plugs" and the dealer said the water had to be sucked out.
Somebody be pulling somebody's leg. Your son might want to read his owners manual.
All of the new MerCruiser engines have the blue drain plugs.
No MerCruiser engines need to have the water sucked out.
All new MerCruiser engines have closed cooling, so no need to drain the block.
They are almost the easiest engines to winterize.
The only "sucking" involved is sucking in the required anti-freeze. But MerCruiser thoughtfully provided an impeller to do that.