The BRP Rotax engine has a closed-loop, self-contained cooling system for the engine itself, but the exhaust and intercooler (supercharged engines) are cooled by raw water, drawn in, then discharged out the back.

The system is designed to be self-draining in all but the Rotax 200, but it's recommended to evacuate (blow out), all the remaining water if your boat will be exposed to freezing conditions for extended period of time.

The process is very simple, as I've demonstrated here. (Remember, if you do not feel comfortable doing this, please take your boat to a dealer. We are not responsible if this is not done correctly.)

Also, consult the engine owner's manual or service manual for more details.

1. Start up your engine, let it idle for 30 seconds or so, then rev it to 4500 RPM 3-4 times, to evacuate any water left in the exhaust system. (Not necessary if you did this when you last pulled boat out of the water, but can't hurt, and is a good idea. Exhaust gasses do the best job evacuating water from the exhaust.)

Do not run your engine more than a minute or so max, and shut off immediately after revving a few times, you do not want to overheat the exhaust.

2. Using an appropriate adapter, connect an air compressor to the flush port on the rear of your boat, near the jet drive.

You can build your own adapter, but it's much easier just to buy one pre-made, here's the one I use and recommend on Amazon. [ Ссылка ]

As I indicated in the video, you must have a large enough compressor to provide adequate air flow into the system to evacuate the water. It's just as much about air volume as pressure, so a small, portable compressor will likely not be sufficient, the compressor must have an air tank, which holds compressed air, and can supply a constant surge of high-pressure air for at least 5-6 seconds per burst. (I have a 30 gallon Craftsman compressor I used in this video, but have used a much smaller one, with a 20-gallon tank, but it's almost painful how slow it is. You must shoot some air in for a few seconds, then wait a minute or more as it builds up enough pressure for each shot. This isn't the case with my large compressor, I can do the whole thing in a few seconds.)

Per the Rotax manual, the pressure should be set for 60-100 PSI, but again, it's the volume of air that matters more here. The air is blowing through the system, not putting (much) pressure on it, so there's no need to worry that you are injecting high-pressure air, very little pressure builds up in the system, because it's open on the other end, and the air just blows through as the water comes out.

3. Using 4-5 second bursts of air, continue blowing air into the flush port until no more water comes out.

4. At this point, your engine is safe from freeze damage. Some people like to draw RV anti-freeze into the system, but there is no mention of this in the manual, and I don't recommend it. Air does not freeze, the best, safest way is by evacuating the system entirely. A few drops of water left in the system will do no harm whatsoever if they freeze, as long as the system is not full of water. (Damage occurs by the expansion of the water as it freezes, and unless the system is full of water, there is no damage that can happen this way.)

5. You must do this on EACH ENGINE separately! If you have twin engines, you need to do this to each one, the cooling systems are not connected to each other!

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This is just a small part of overall boat winterization, so please see my full winterization guide in our Chaparral Vortex Boat Owner's group, for more details, or to ask any questions, thanks, and good luck!

[ Ссылка ]

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