Just curious, what is the benefit of using anti-freeze over just pulling the plugs, draining the block and going on? I live in Tx and plan on using the boat as much as possible. I will use/start and run at least once a month even during the winter months. Any input? Thanks

I've always been a proponent of draining everything. If somebody really wants to use anti-freeze, I always recommend draining the whole system, putting the plugs back in, then filling the whole system back up with anti-freeze. Why? Because that's the only way to guarantee you have a proper mixture / concentration of the solution everywhere. I don't like taking chances. You might note that most marinas - especially up north - don't use anti-freeze. We drain for our own liability protection.

So why do so many folks like anit-freeze as opposed to draining everything? Slapping a set of muffs on and running anit-freeze through everything can be faster. And, if you have a boat where some (or all) of the drain plugs are a real pain to get to, it's a hell of a lot easier on your body.

after much thought and time in thinking about this i just decided to get it done i ended up draining the block and exhaust loosening the hoses from the thermostate housing and pouring anti freeze in all the hoses. filled up the block, the cooler line flushed through to the out drive, and left the riser plugs out and and poued anti freeze in exhaust hose until came out the riser plugs, once i decided to just do it instead of looking for a easy way it took about 40 mins. Did i miss anything.

later

Good thing you posted back in because what you did would not have worked. Assuming what you have is a standard small block Chevy based Mercuiser, here’s what I do:

• Add stabilizer to the fuel and running off the muffs, make sure it gets up into the carburetor.
• Fog the engine by running fogging oil through the carb until all of the mosquitoes in the area die. (Lots of white / blue smoke.)
• Drain the power steering cooler on the bottom port side. New ones have a drain plug. Older ones require you to remove a hose clamp and hose to drain.
• Remove both block plugs – one on each side and run a wire, awl or zip tie into the opening to make sure any sediment blocking the drain is removed. You should get a nice, smooth flow of water out of each one.
• Drain both exhaust manifolds. Newer ones have drain plugs at the center bottom. On older ones you might have to remove a hose clamp and a hose. Same deal with unplugging the drains with a poker.
• Drain the water circulating pump on the front of the motor. (It’s what you would call the water pump on your car.) Do this by removing the lower end of the large hose on the starboard side.
• Drain and refill the drive from the bottom drain on the front / side of the gear case. Remove the top (vent) plug to assist draining and refill from the bottom until it comes out the vent.
• Thank your friends at OSO for saving you a small fortune.

BTW, Sorry if I got a little too basic with this post. I don't mean to insult anybody's intelligence.

Did both of my cruiser motors today, 350/Alphas

I did this this while on the lift. Removed all the drain plugs and the lower hoses to empty the motors, reinstalled. A 5 gal bucket on swim platform, hooked to muffs for gravity feed. Fired them up and ran 6 gal of AF thru. When I got to the last inch of AF, hit the carbs with a fog to choke it down.

Ok, now you guys got me worrying. I recently bought a boat with twin 496 Mags w/ closed cooling. All I did was run each motor on muffs to get up to temp, then cranked it up and pumped 5 gallons of AF in (AF was coming out the back when I shut it down). I have winterized my VP 496 (raw water cooling) this way for years and never had a problem. Of course it doesn't get REAL cold here in the south, but we do have short periods of low teen temps occaisonally. I first went by the "Merc Instructions" and simply used the little pump on the front of the motor and "pumped" the water out into the bilge, but this just didn't seem good enough, too much chance of leaving a little water in the heat exchanger. Since these are MPI, I didn't fog but put Stabil and Sea Foam in prior to warming them up. Do I need to do something else?

Also, I changed the oil with Mobil 1 5W-50, ouch! 18 quarts of this stuff ain't cheap!

Once mine is done I do not have access to it 'til spring. I like to use anitfreeze because of its anti corrosive properties. You don't get any extra protection against rust by just draining and letting it sit for six months. To further protect I go to town with WD40 on just about everything in the bilge, the drives, tabs, trailer jacks, winch....you get the picture.

Merc says to take off the fuel filter and pour off half the fuel, add 2 stroke oil to the filter and re-install. Then run the engine on that for the last minute or so while you add antifreeze. This takes the place of fogging.