If you are using RV antifreeze and you are not draining the block before running the antifreeze through, you are dilluting the antifreeze with water due to recirculation of the existing water in the block. Always drain the block first if you are sucking pink up through the drive with muffs.

Plus you remove any sand or junk thats at the drain plug areas.

Does pink anti-freeze protect the innards from corrosion?

Prestone RV anti-freeze does and says it on the label. Although I think some other types don't, so be sure to read the label.

We warm it up on the muffs making sure the themostat is open.

We just fill a large bucket with pure antifreeze and jack it up (old sizzor jack with plywood) over the drive covering the pick ups. It will suck it right up uses about 5 gallons, checking for antifreeze in the exhaust, then we refill and do it to the other engine. In the spring we flush out the engine BEFORE we get to the river.

...yes it will take more if you dont first drain the block!

I always drain the block, for the above mentioned reasons, but i always let the motor suck it up, not gravity fed going down.....

I have been using this kit for years works awesome.

http://www.boatersworld.com/product/178050035.htm

And after you finish with the antifreeze drain the gear case and change the lube or in the spring you might have an engine that runs but a gear case that is cracked from water mixed in with the lube. Fishing line is a killer to prop shaft seals.

The right way to winterize is to drain your engine block and exhaust manifolds, all your lines and oil cooler too. then remove the t-stat and fill the engine with real serria ployprolene coolant the safe coolant for the green guys and ducks and fish people dont waste your money and take a chance of having a crack engine block in the spring time by using RV antifreeze crap. and in the spring drain the coolant out and refill the engine and manifolds with fresh water and fire it up on the muffs in the drive way.and save the coolant for next time.