“I fly with a Rotax 912”
Mod – you may want to move this.
In the UK 912 equipped aircraft do not normally have carb heat. This is due to the higher under cowl temps possible with a water cooled engine. My own MCR does not have one and has never suffered. Having said that if it is fitted I would check the POH (if there is one) and follow the advice given. If your aircraft is on a permit there are some uncertified options to heat the body of the carbs which are on all the time and may be of interest.
Rod1