gmt

arboldt,

I used my method last year and it worked fine, had a good winterization. I will use the same method this year.
Regarding the anti-freeze, I used something that was labeled low toxicity, but I did specifically see that it was for RV's.

I would think that it does not matter what you use and long as it has enough low temp rating for the region you live in.

Gordon

OK,
I winterized with antifreeze through the flush port as planned. I hooked a hose with a quick connect to the flush adapter and then had a funnel on the other end of the hose elevated to the level of the tower. Without the engine running I poured full strength antifreeze into the funnel. After approximately 1/2 gallon of antifreeze was poured an interesting thing happened. Old river water was draining out from under the boat, out of the grate. It was as if the antifreeze pour was pushing the old water out of the system. In fact, that WAS what was occurring because after approximately 3/4 of the gallon was poured, antifreeze began leaking from the bottom of the boat, through the grate.

If things worked as planned, the leaking antifreeze is coming OUT OF the intake hose at the the jet pump/venturi area. The antifreeze is flowing by gravity and a capillary effect in a retrograde (opposite direction) fashion through the cooling system.

I needed to test things. The first thing I did was take off the hose on the top of the exhaust pipe, the exhaust bleed hose. I saw antifreeze in here. I did a test, putting more antifreeze in the funnel and it comes directly out of this hose. This hose is normally a heated water outflow hose. So the Flush Port is really just this hose.

The second test I did was to take off the hose at the top of the intercooler. This hose normally would take water out of the intercooler and bring it to the engine exhaust manifold. I did a test, putting more antifreeze in the funnel and it came up out of this hose. That meant that the antifreeze flow was retograde through the engine exhaust manifold.

So after these two tests I felt comfortable that antifreeze went through the engine and the intercooler. I assume that antifreeze would have dripped through the exhaust pipe water jacket into the muffler area also, but I have no way to test that.

In the future I will trust this technique and not spend the time taking off the hoses. As you know the intercooler hoses are not easy to get to. This will be quite an easy technique.

I did not blow compressed air through at any time as Pete described. Although I think that is an interesting idea I did not do it. I am not sure of the design of the inside of the intercooler and I wanted to keep the system full of fluids and not have any air fluid interfaces that might cause a vapor lock effect.

I have attached some pictures.

Thank you to those who posted to the original topic.