Antifreeze won't go in

[Deadline]

On my Yanmar 2GM20F I couldn't get the antifreeze to siphon in.
Funneled it correctly to T-valve in the raw water intake line.
Perhaps a half a gallon slowly went through in 20 minutes.
Tried opening the valve to boost the flow, which worked before.

The engine was warmed up, but only to 120 degrees.
That doesn't matter because it has to cylce regardless.

Mine's a 320, where the exhaust pipe is below the water line.
So I can't tell if water is actually getting pumped out.
Finally stoped for fear of destroying the (new) impeller.

It must be pumping water, since I've run the boat lots.
But it's crazy to imagine the engine going without raw water.
Gravity and the water pump should suck it through, right?
I'm checking to see if the raw water intake lines are plugged.
Otherwise, I'm flummoxed. Any help appreciated. Thanks.

 

[Scott]

Maybe your siphon tube is clogged. Close your intake seacock, remove the raw water strainer, then try pouring the anti-freeze directly into the in-take.

 

[Jerry Clark H356 SV Persi]

You need more than idling RPM to make it flow. Try again after checking things above, put in neutral and add some power to increase RPM. If that doesn't work, check your impeller - you may have burned it up. Look into a Speedseal.

 

[Dave602]

I went down below with two gals of anti freeze, closed the seacock, opened the strainer and had the wife fire her up. I poured antifreeze in until she saw a good stream of pink from the exhaust. worked pretty well.

 

[Alan]

I have a very simple procedure for you. Close the raw water seacock, remove the hose and insert it into a gallon of anti freeze. Start the engine and watch the level in the gallon container go empty. Shut the engine off, you're done. The entire procedure takes barely 2 minutes.
BTW the pump will work fine at idle or not, pump speed is not a factor.

 

[Warren Milberg]

I winterize my 2GM20F exactly as Alan states, i.e., close the raw water intake seacock and put the hose in a gallon of antifreeze, then start the engine. This engine only needs 1 gal to wnterize and it should get sucked up in less than 2 minutes. I cannot imagine it taking 20 minutes without something being really amiss, like the one of your hoses being clogged or crimped or, more likely, air getting into the system from a loose clamp.

 

[Bill Roosa]

Why are we winterizing the raw water side? I've always just drained it of water. The small amount of water in the exhaust and muffler (there is a drain on it BTW) left will not be sufficiently confined to break anything.

 

[Claude L.-Auger]

It is cheap insurance

Why are we winterizing the raw water side? I've always just drained it of water. The small amount of water in the exhaust and muffler (there is a drain on it BTW) left will not be sufficiently confined to break anything.

For those of us in solid freeze areas, it is cheap insurance to winterize the exhaust system completely. Depending on boat model, drain valve on muffler not always easy to reach. And, if you really want to be chintzy about it, since you must recuperate the antifreeze in the Spring to prevent pollution, you can save it and use it again the following winter ! Make sure you also test the fresh water system for the temperature you want to protect against.

 

[Crazy Dave Condon]

If using the non toxic RV antifreeze, you are safe. Never use the kind you put into a car radiator as it has PCB's

 

[Alan]

Crazy Dave, EG (green) is also poisonous but why would you care when winterizing the raw water cooling of your engine? it's not as if you will be drinking the stuff.