That is the way I use to do it until I pulled my engines in the winter, and found the blocks were full of frozen water. I was lucky and nothing was cracked, but that was the last time I ever stored my engines without draining them first. I would alway run at least 5 gallons of antifreeze through each engine, once up to temp. I'd rather have some rust and goop in the bilge than cracked blocks. Its easy to hose out a bilge, not so easy to replace cracked engines.

Not only that but I kinda like to the rusty scales and black goop etc out of my blocks if it was in there. The beauty of this simple set up is you can drain every so often to prevent build up of any kind including sand potentially causing hot spots in the blocks. Might not be for everybody but sure is slick.

You can also use a T fitting and cap one end and simply have another hose handy for draining through drain plug. Not a bad idea to put some air pressure to the lines occasionally also just to make sure they don't scale over. Especially if you only drain once a year.

Nice. I'll take pics of mine this fall when I build something.

Wow,.... I see frozen busted blocks happenin' all over the place,.....

I use plain ole brass hex-head pipe plugs, 'cause ya Gotta probe the holes in the block to dislodge the sand, silt, 'n rust to drain it proper,....

Run antifreeze if ya want, but ya Still gotta drain the block 1st,....

Otherwise, eventually, you Will Freeze, 'n Bust yer block,.....

I drain, 'n store Dry,.... Never had a busted block in over 40 years,....

1/4" ball valve right off block easiest and cheapest thing, don't use long nipples they can break under rough water conditions, shorter is best

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I antifreeze and then drain locks and exhaust, sea pumps, as much as ican, I store in conditioned space but still drain

Nothing wrong with that either. I understand what Bondo was getting at also by not reducing down due to scale etc blocking the drains. With or without sea strainers I still think it's a good idea to drain blocks a couple times a season to avoid any kind of build up. All I know is if I don't get a gallon + or - out of each side there is potentially some blockage. When winterizing as long as I get two gallons in I'm comfortable.

I use to wintereize completely different with great success by running on muffs til stats open and immediately run 5 gallons of antifreeze through with short hose and plastic can laying on swim platform etc. Was kinda nice cause I didn't have to remove or anything. Now I just like to drain blocks and fill. "Just my preference". But if I didn't have any way of measuring to a degree how much water drained from blocks I wouldn't trust method used. Like endeavor32 mentioned it's amazing how much build up one can get in a block. Sea strainers prevent a lot of this however will still get scale.

I never had many issues with blockage, worse case a thin screwdriver fixes it I leave all valves open all winter

You guys must have easier access than what I have in my Formula. You are not getting anywhere near the drain plugs in my boat. I've tried every possible thing I could think of and I alway came up short. Never short on a few good curse words, but certainly short on progress. With the system I described I drain the blocks, blow air back up the hose, then if the block are done draining, dump some antifreeze in the block and if it comes out the hose, I'm done. Pretty much zero chance there is going to be any issues come the spring.

The best part is it's fast, easy and no frustration.