Winterizing Mercruiser Through Inline Strainer

[Rickochet]

I have two 2001 5.0 EFI Mercruisers/Bravo II units in my houseboat that I leave in the water all of the time. It has raw water cooling that comes through the outdrive to the engine mounted seawater pump.

I recently had the boat hauled to the factory for storm damage repairs and while there had some strainers and ball valves installed in the line from the outdrive to the seawater pump. The strainers are the clear plastic top type. I can see water flow and easily remove the top with one wing nut to clean out the filter. I have the same strainer on my Westerbeke and all I have to do to winterize it is to shut off the valve and pour antifreeze in the strainer until it comes out the side of the boat.

I was hoping winterization through the engine strainers would be as easy as the gen. Last fall I ran both engines until they got up to temp. I then shut off the valves., restarted and poured a 75% antifreeze mix in until it came out the outdrive. I think it took six gallons to do each. Since it was the first time I did this I checked the six blue wing nut drains. The manifolds were nice and green as were the cooler and circulating pump. However, when I opened the block drains out came clear water. I don't understand this. I did this immediately after running them to temperature so the thermostat should have still been open. Just to be sure I drained everything and filled the block up with antifreeze mix in the thermostat well as I always have done. I was hoping to not have to mess with the blue wing nut drains anymore as they are very difficult to remove and put back for a large dude with big fingers.

Any ideas on why the antifreeze mix didn't get into the bottom of the block? Would two more gallons of antifreeze mix do any different?

Rick

 

[Dave1251]

Re: Winterizing Mercruiser Through Inline Strainer

Many people have replaced their engines in the spring trying to winterize this way. This method of winterization only works if your engines are fully warmed up and your sea water pump is in good condition.

The only way to winterize and not be at risk is to drain the engine by removing the blue plugs and hoses.

Also, green antifreeze is not good for in water winterizing, something about killing the fish near your boat. RV anti freeze is the only way to go.

 

[Rickochet]

Re: Winterizing Mercruiser Through Inline Strainer

Many people have replaced their engines in the spring trying to winterize this way. This method of winterization only works if your engines are fully warmed up and your sea water pump is in good condition.

The only way to winterize and not be at risk is to drain the engine by removing the blue plugs and hoses.

Also, green antifreeze is not good for in water winterizing, something about killing the fish near your boat. RV anti freeze is the only way to go.

Sorry, but I don't buy that, particularly with the Bravo II drive that has the big seawater pump on the engine. That may be true for those with the Alpha drives with the impellers in the the lower unit who might try to do this with a muff adapter.

Also, everything I have ever read suggests that RV pink antifreeze has zero lubrication or anti-corrosion properties.

Edited: I got a call back from Mercruiser. Their tech told me that my set up was fine for winterization. He told me, however that I would need about 10 gallons of solution to properly winterize each engine that way.

An option I am now thinking about is to start the engines cold with the thermostats closed and pour antifreeze in the strainer until it comes out the outdrive. That will at least winterize the pump and hoses without having to fight with them. Then drain everything the old fashion way removing the blue wing nuts and fill the block up through the stat hole.

 

[Jeepster04]

Re: Winterizing Mercruiser Through Inline Strainer

Could you take the stat out and run the engine like that so you dont need to worry about it being warm?

About the RV anti freeze, does the water in the lake keep down rust when its not winterized? What does it matter if it has RV antifreeze in it?

Personally I would be able to sleep much better if the block was drained and antifreeze was added. You should think about not putting things in the water that shouldnt be there though.

What kind of house boat do you have? We personally have a stardust. Before you had the valves and the water came through the outdrive, did you just leave the hose on when you winterized it or did you take it off the tube coming into the boat and plug that tube off? The guy that winterized our engines last year left that hose on and Ive often wondered how that works. I guess he drained that hose and water wont come in unless the engine is started? If that tube coming into the boat above the water line? Ours may be different, idk. It has Dual 5.0 Volvos with DP out drives.

 

[Don S]

Re: Winterizing Mercruiser Through Inline Strainer

I'm with Jeepster, you don't have any anti corrosion/rust protection all summer, why worry about it in the winter. Drain the cooling system and and be done with it. Air doesn't freeze nor pollute your lake.

 

[Rickochet]

Re: Winterizing Mercruiser Through Inline Strainer

What kind of house boat do you have? We personally have a stardust. Before you had the valves and the water came through the outdrive, did you just leave the hose on when you winterized it or did you take it off the tube coming into the boat and plug that tube off? The guy that winterized our engines last year left that hose on and Ive often wondered how that works. I guess he drained that hose and water wont come in unless the engine is started? If that tube coming into the boat above the water line? Ours may be different, idk. It has Dual 5.0 Volvos with DP out drives.

We have a 2001 Sunstar. The president of Sunstar was a former partner in Stardust and our hulls are identical as is most of the other boat features.

My cooling water still comes in through the outdrive. I just added the valve and strainer in the hose that runs from the outdrive to the engine mounted seawater pump. Before I installed the strainer I would take the hoses off of the pump and drain them and plug the hose from the outdrive and tie it to the engine above the water line. Getting that big stiff hose off of the pump while standing on your head is a royal PITA.

 

[Rickochet]

Re: Winterizing Mercruiser Through Inline Strainer

Well, I have been doing some research on notox and low tox antifreeze. Apparently all pink antifreeze is not the same. Some have anti-corrosion additives and some do not. The Seafarer brand is advertised as having the anti-corrosion additives and is recommended for engine use.

I read a lot of arguments over using the pink stuff. I guess it boils down to using the proper pink stuff. I know putting a bowl of ethylene glycol antifreeze in a bowl in your yard will kill animals. I don't know how much of a danger this is when diluted by a bazillion gallons of lake water. But since I don't know, using an appropriate non tox stuff is the responsible thing to do.

So I guess I will run the pink stuff through the pumps with the engines on. Then drain the enginess per the specs and fill the blocks up. Or maybe I will hire someone younger and smaller than me and I will supervise. I am getting to old for a lot of this stuff.

Thanks to all for all of your input. If anyone has a good internet source for a good pink antifreeze I would appreciate that.

Rick

 

[Jeepster04]

Re: Winterizing Mercruiser Through Inline Strainer

Thanks to all for all of your input. If anyone has a good internet source for a good pink antifreeze I would appreciate that.

Rick

I would also like to know a good source for anti-freeze. After doing 3 engines and winterizing the interior of the boat youve gone through more than 20 gallons of the stuff. I guess you dont need pink stuff with anti corrosion for the plumbing inside though.

Thanks for the info on the hoses. I hadn't though of taking it off of the pump and putting it up high. What do you plug it with? Do you worry about the pipe coming in from the out drive(the solid line the hose clamps to) freezing and cracking? I dont understand why it doesnt crack if it always has water int it???

 

[myoldboat2]

Re: Winterizing Mercruiser Through Inline Strainer

The "non-toxic" stuff is made from propylene glycol instead of ethylene glycol. I actually got part of a drum of food grade propylene glycol years ago. Made for chillers, it has an anti-corrosion package and is safe for human consumption. I've been cutting it with water but I've been looking for some cheap non-toxic windshield washer fluid to cut it with. After reading this forum, I'm probably going to just start draining it in the future, maybe pour some antifreeze in the hoses. I suppose I'll decide in a month or two.

 

[Rickochet]

Re: Winterizing Mercruiser Through Inline Strainer

The "non-toxic" stuff is made from propylene glycol instead of ethylene glycol. I actually got part of a drum of food grade propylene glycol years ago. Made for chillers, it has an anti-corrosion package and is safe for human consumption. I've been cutting it with water but I've been looking for some cheap non-toxic windshield washer fluid to cut it with. After reading this forum, I'm probably going to just start draining it in the future, maybe pour some antifreeze in the hoses. I suppose I'll decide in a month or two.

I found some propylene glycol -50? with anticorrosion stuff on sale on the West Marine website for $3.99 per gallon (part#499848). Just for grins I ordered 20 gallons to see what the shipping was. Shipping showed up at $9.95 for the order so I ordered it.

I ordered it on the 14th and received it today via Fedex in three boxes 6 gallons per box and one with two gallons. And credit card charge was indeed for $89.75. A shipping charge of $9.95 for 180 lbs of product is pretty amazing.