Plugged....?
That water hose fitting type flush port should be left open at all times. This is our open loop cooling water outlet. If you plug it, then the only water leaving your engine during operation is through your tail tell tube and the water injection to the exhaust. I'm surprised you didn't get the over heat alarm.
You asked about winterizing. There are a gazillion threads on this and a few stickies. But, since you took the time to actually PM me, that means you have some concerns about your boat, I can appreciate that.
Your motor, the Rotax, uses the total loss cooling system. You should not have to worry about busting a block, etc.... like you would from a car. But, there are pockets where water can sit up and freeze. Therefore, we add antifreeze to our engines.
If you are going to store in an insulted building, you could do away with winterizing all together, especially if you could start the motor once every two weeks. On the nights when temps will fall below zero, you can place a light build in the engine compartment, aft of the PTO, pointed toward the motor. You must use extreme caution in this situation if your boat has any kind of fuel build up or leaks into the hull.
If you want to winterize, the battery should be removed when you finish with all your steps and kept in an area above freezing with no extreme temp changes.
Looking at the engine, you have 2 hoses connected to the head. The one on the left goes it your water supply from the pump. Pinch that hose. On the port side of the engine, you have a small line, usually clear or discolored over time, that is coming from your cylinders to the rear exhaust water box. Pinch that hose too. Now, looking inside the engine compartment, where the upper flush connection and the one you see going out the back come together, pinch the one going out the back.
Go to your auto parts house and buy a gallon of that 50/50 premixed coolant. Pour this in with a funnel where you would normally connect the hose for flushing until you see if come out the "tale tell" line, which is the highest point of your motor.
Now, un-pinch all your hoses I mentioned to pinch. Most of the coolant will run back out but the areas of pockets will now be protected from freezing.
You should use WD-40 to liberally spray the entire engine, this will provide a moisture barrier and keep rust from forming.
Last, I use a Lithium Spray, which you can get from your local auto parts house. Lithium is a grease used during engine rebuilds. It also provides a barrier where metal to metal parts meet. This will too keep rust from forming. Take out your plugs and spray it inside the plug holes. It's a good idea to grab your PTO hub (take off the cover) and spin it counterclockwise when you are doing this. You do not need to use that expensive "bombardier fogging spray".......also, spray a bit through your carbs, air box removed. This will put some grease protectant on your rotary valve.........:cheers:
