I believe that the carbs compensate automatically for changes in air density e.g. due to altitude, temperature. So no need to disassemble and change the carb between seasons.
Wasn't assuming. Which is exactly why I asked. Also, it literally says in the maintenance manual that you may need to change the carb circlip position to account for seasonal changes. This will be my first season owning a rotax powered plane. A recognized expert in Vic Syracuse stated in these forums that he changes his 2x per year (Sumner/Winter). Net, I think it's a valid question and smart to desire to understand our engines as much as possible.As long as people don't screw with their engines, a Rotax will last forever. You're suggesting screwing with it. Don't assume you know more then the designers. Unless you only fly in Denver and NEVER get lower, don't screw with it.
Curious with the colder weather coming (at least in northern latitudes) if anyone adjusts their circlip position on their 912ULS?
Or said differently, on what notch do people keep their circlip in summer/winter or elevation?
At 400 hours I solicited help on my carb inspection by finding an old school carb guy in the Denver area. We talked about and reviewed the condition or sootiness of my plugs and decided to move the needle cir-clip to the third position. I haven’t had a need to check the plug condition now at 465 hours.
Starting and normal operations through the summer have been good, fuel economy the same as always, and my hope is for cleaner looking plugs. Annual happens January into February and I will change all the plugs then, and will document their condition.
I don’t think I would changed the cir-clip position had I not gotten guidance from someone having a lifetime of carb knowledge. He didn’t have any Rotax experience but was very familiar the Bing carburetor.
In the midwest USA where summers are 100F degrees and winter can easily be -10F I would think moving the clip a notch at some point would be wise. I think I recall seeing a post from Vic Syracuse (in Atlanta) where he moves his one notch in the winter and back down a notch in the summer.