plugs in or out after antifreeze

[Coz]

Last year the dealer winterized my boat as part of the sale. They ran antifreeze thru the engines, then removed the drain from the distribution fitting and the maybe the seawater pump (don’t recall).

I figured you would leave plugs in to help prevent corrosion

Ive got the 3 point drain system.

 

[JimG]

I drain the water and put the plugs back in, then fill with anti-freeze.
When spring comes it's ready to drop in the lake.

 

[Leardriver]

I leave the plugs out after anti freeze. I'll take my chances with corrosion. Antifreeze can gel up and freeze, and by leaving the plugs out, any stowaway water is pretty much evaporated before the first freeze.

 

[Mknupp]

What Jim G said!!

 

[Seapig]

Plug stay in to keep the antifreeze in place.

 

[Blueone]

With my 350 MAG's I stored indoor cold and always left the blue plugs out after using antifreeze.... One reason was they were a pain in the ass to get back in and I always felt better leaving it to spring when I would be in a happier mood

 

[Chip S]

With my previous boat I would pull the plugs to drain the water, put the plugs back in, and then run pink antifreeze through the system to remove any residual water that didn't drain out. The pink antifreeze contains corrosion inhibitors so I left it in.

With my current engine (Mercury outboard) I just make sure its in the vertical position to drain all of the water out of the system. Done!

 

[b_arrington]

On the 350MAG with the air pressure drain system (and maybe others), there is a blue drain plug at the bottom right of the engine (when installed with an IO). Even when using the air drain and after running pink though the system, water can remain in that area. The round-ish part the plug fits into can hold water causing both it and/or the plug can crack. I found out the hard way.

I would recommend to minimally open all the lower plugs to ensure there's no water left in there, and preferably that our get some pink to drain out. Then tighten the plug. Image of the area below.

 

[Lazy Daze]

I would recommend to minimally open all the lower plugs to ensure there's no water left in there, and preferably that our get some pink to drain out. Then tighten the plug.

Excellent advice. I always wait to put plugs back in - no matter the type of system - until I see some pink coming out. Even with "regular" systems where I remove individual block drains, and such, and then poke the holes. Consider it a "sacrifice to the winterizing gods"

A side note to the quick drain system... and this could very well explain the issue you had... The hoses that go from the block and exhaust manifold, down to that water manifold are small (diameter). It's not uncommon for them to get blocked with sand/muck/etc. When that happens, it will appear that all of the water has drained out from the water manifold/plug. But what happens is that there really is a little water still left in the system and it slowly works it's way down to the manifold. The antifreeze that is put into the block is enough to push the water down into the manifold, but likely doesn't mix completely with that water... hence the eventual crack. You're not alone when it comes to that experience.

But to answer the question... on my boat, the ones I winterize (side job) and all of the hundreds and hundreds that come through the shop... yes, I/we leave it in.