drain plugs

HELP please. I have 7.4 Mercs with V drives. I read about drain plugs. I found two drain plugs on each engine. I pulled one of them out and antifreeze starting coming out. Do I need to pull different drain plugs? The salt water comes up through the sea strainers for the exhaust. I was...

Arguments I have read sound like as follows: a) Use Muffs to bring in af. It's easy to miss a plug, and if you do, you won't fully drain the block and will end up with a cracked block. b) Drain block and backfill through thermostat housing. It's what Merc recommends, and the muff method just...