Winterize engine in the water ?

[Delawaredave]

1984 Hunter, Yanmar 10GM.
Boat is in the water. Can we winterize the engine now before pulling it out for winter ? (they tow boat to lift, not run engine)
Cut off river intake, funnel antifreeze into water pump input and run engine until antifreeze comes out back.
Will river water come back in through the exhaust back into engine pockets ?
Appreciate any input - thanks !

 

[Bill Roosa]

Air does not freeze. Turn off the thru-hull and drain the system. The little water in the muffler has room to expand so no worries. remove the back/front of the water pump and pull the hoses. I've been doing this for several years with no bad results. BTW the same thing works for the fresh water system. Just use compressed air to blow out the lines after draining (mostly) the tanks. You just have to take off the intake and output hoses to the pump to blow them dry. A much greener solution IMHO and not bad taste come springtime.

 

[Rich Stidger]

My normal procedure is to winterize my engine and generator while in the water. I close the seacocks and attach a hose to my raw water strainer. Years ago I made a special fitting to accomplish this task. The open end of the hose goes into a bucket fed by a fresh water hose. I run the engine for 10 minutes minimum and then until hot. This flushes all the salt out of the engine. Then I immediately change the oil and filter and refill with new oil. Next I move the hose to a second bucket with 50/50 antifreeze and run the engine until a pre-determined amount of antifreeze has been sucked in. I have previously measured the freeze point of the antifreeze that comes out the exhaust so I know how much to pump through to attain a -25 F freeze point for the engine and the generator. That's it until after hauling. After hauling I open all the seacocks everywhere and let them drain, then close them for the winter.

I think that one of the advantages of filling the engine raw water passages with antifreeze instead of air is that air will promote the internal rusting of the engine and the antifreeze fills all the spaces with corrosion inhibitors. I once had an Atomic 4 in another sailboat that the PO told me to simply drain the cooling passages. The first year I did this and was rewarded with a rust-blocked exhaust manifold. Thereafter I always filled the block with antifreeze and never had that problem again. YMMV.

I do however blow out the fresh water lines and drain the hot water heater. I have never added antifreeze to that system, so like Bill I never have a bad taste to flush out in the Spring.

 

[njlarry]

Maine Sail has a great video on winterizing on the hard. I use his method in the water. I pump four gallons of pink antifreeze through the raw water side by disconnecting the discharge hose from the raw water strainer and placing it in a two gallon bucket with the antifreeze in it. As it drains I add the rest. The admiral catches the exhaust discharge with a small bucket on a boat hook and I check it with a refractometer to make sure that there is full strength AF in the whole raw water side of the system. Very easy and takes less than 15 minutes. I rest well knowing that there are no pockets of water to destroy the engine over the winter.
For the drinking water system I run the tanks dry, drain the water heater and then by pass it, then pump about two gallons of AF by inserting the intake hose of the water pump into the gallon jugs. The tanks stay virtually empty and disconnected from the pump. About one half gallon is pumped thru the head and into the empty holding tank.

 

[SailormanDan]

I have a Yanmar 1GM in my H27 that stays in the water all year long. The original (typewritten) winterization instructions I have actually say to shut off the intake and run the engine until there is no water coming out the back, which is similar to what Bill is talking about (the little bit of water left won't hurt anything). Did this for several years without issues. I added a strainer between the intake and the pump which has a cap I can open and add antifreeze and I do that now if I'm out in the cold.
I also do not put antifreeze in my fresh water system, it leaves a taste that I notice. I tape a wet/dry vac to the spigot and suck the water out, never thought about blowing it in the other direction.

 

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[Bill Roosa]

SalormanDan
I like your idea of sucking the water with a wet/dry vac. You learn something new every day

 

[Randall Schmidt]

do you have a pressure water system? does it make a difference in terms of using the vacuum approach?
When you vacuum out the water from each spigot do you first run them to drain them and if so I'd think there would be no water left to suck out.

 

[thinwater]

My normal procedure is to winterize my engine and generator while in the water. I close the seacocks and attach a hose to my raw water strainer. Years ago I made a special fitting to accomplish this task. The open end of the hose goes into a bucket fed by a fresh water hose. I run the engine for 10 minutes minimum and then until hot. This flushes all the salt out of the engine. Then I immediately change the oil and filter and refill with new oil. Next I move the hose to a second bucket with 50/50 antifreeze and run the engine until a pre-determined amount of antifreeze has been sucked in. I have previously measured the freeze point of the antifreeze that comes out the exhaust so I know how much to pump through to attain a -25 F freeze point for the engine and the generator. That's it until after hauling. After hauling I open all the seacocks everywhere and let them drain, then close them for the winter.

I think that one of the advantages of filling the engine raw water passages with antifreeze instead of air is that air will promote the internal rusting of the engine and the antifreeze fills all the spaces with corrosion inhibitors. I once had an Atomic 4 in another sailboat that the PO told me to simply drain the cooling passages. The first year I did this and was rewarded with a rust-blocked exhaust manifold. Thereafter I always filled the block with antifreeze and never had that problem again. YMMV.

I do however blow out the fresh water lines and drain the hot water heater. I have never added antifreeze to that system, so like Bill I never have a bad taste to flush out in the Spring.

Bad taste is the result of several common mistakes:
1. Water dilution. AF that is less than 25% glycol can ferment and get nasty. Use enough. Common mistake.
2. Too long. Don't winterize until it's cold, and break winterization early. Less time for 1.
3. Never add water to the tank. Vac it MT.

Either way, add valves so that you don't have to break fittings.

I've never had a bad taste either.