I have an 01 Tige V-drive with a heater.
I decided to try something new this year. I directed all of the exhaust water into a bucket. I filled this bucket up with antifreeze and hooked up a fake-a-lake to the bucket. The antifreeze was circulating, but I'm not 100% sure if it was ever recirced through the block. I'm pretty sure it was because the thermostat was opening and closing, etc. I think one of the problems that I created for myself is that the anti-freeze being dumped into the bucket was really hot, so I started overheating the engine.
The other strange problem I have is that my heater lines are not getting hot...I ran the boat for 10 minutes with a fake-a-lake at about 2500 RPMs, and the lines were cold...any ideas?
The reason I wanted to do this method is that it's easy with one person and i figured I wouldn't have to blow out the lines to the heater core...