14. Disconnect the water and muffs and allow the water to drain out of the drive. Now get your manual and remove every drain plug on your engine, manifolds, coolers, heat exchangers, water pumps, and anything else that could have RAW water in it. Look at the book and make sure you have them all removed. Look around, missing one could cost you an engine block. Get a small screwdriver and probe inside every hole you remove a plug from. Make sure there is nothing blocking the water from getting out. Be sure the engine is also as level as possible so as much water as possible is drained out. Some of the coolers for oil and power steering can be drained by removing a hose easier than removing the plugs.
Put all the plugs back in and hoses back on.
If you are one of those that must use antifreeze instead of just draining, for whatever reason, you can fill the block and manifolds with a 50/50 water/antifreeze mix through the hoses to the manifolds and coolers and removing the thermostat and pouring antifreeze into the engine block. Many of the RV type antifreeze do not have corrosion inhibitors in them because they are meant to be used in the domestic water system.
!! Now listen to Bondo and just drain everything like he suggested. Then after you have gotten the raw water out, if you want to go ahead and add some RV antifreeze back in that is fine. Do that and everything will be OK in the spring. Geez went out to You Tube to see if there was a video that uses the Mercruiser manual procedures. I could not find one, so I am not surprised that folks are using the RV antifreeze/muffs method:facepalm:. Man I love my 470 in October
