It doesn't say where your from. Your geographical location, is actually the best way to know, exactly how much you need to do to protect your investment. In my situation, I ride most of the year, but when it's going to get below freezing, I just take the seat off, put a light bulb beside my engine block.
The Explorer has the 657cc engine in it, nice motor, low maintenance. Like I said, depending on where you live, will be a big help. Lets just do the simple stuff. The Rotax engines are what they call a TLCS (total loss cooling system) engine. Which means, when you bring it out of the water, all water in your cooling jacket of your jugs, is suppose to drain out, so no need to worry about your pistons. There is a downside to that. With the age of your motor, and if you've run the motor close to the bottom, then you could have picked up sand and it's stopped up those holes, and the jugs may not drain. The only other part your worried about is your exhaust system. The Rotax using water induced to create power, by using resonance in your exhaust system. If you pinch your hose, your putting coolant in your piston area, but maybe very little in your exhaust system; which really isn't a big deal, because it should never be full to the extent that if it freezes, it would crack anything, cause there is plenty of room for expansion.
Unless your in New York, or Canada, I'd forgo all that anti-freeze stuff, and just put your a light bulb in the engine block during the cold times of the year. I have also used a small space heater, from my shop, but if you even think of doing that, you got to leave your engine compartment cracked open to keep fumes from your gas tank from building, creating an explosion hazard.
Shoot me a PM, let me know where your at. Or, post here and I'll check back. Oh, if you are going to shut down for the winter months, take out your spark plugs, take about a cap full of Marvel Mystery oil, and pour in each cylinder. With the plugs out, the engine will be easy to turn over by hand from the PTO side. Spin it over a bit, just to make sure you lubricate the cylinder walls.
Let me know where your located. You don't have to overdo it, but I don't want you to not do enough either.
