Re: Road trips...
Nearly all the light aircraft using the Lycoming and Continental type engines (so the Cessna and Piper 2 and 4 seat singles and their ilk) have that system for carb de-ice.
The usual effect of pulling the carb ice knob during your standard en route checks out is a reduction in power, but at cruise it doesn't get rough. If you have encountered some icing then you are likely to get an increase in power as the ice melts through.
When testing the carb heat on the ground during pre-flight power checks, there's a max RPM drop allowable that will be shown on the checklist. Like the slight RPM drop when the alternate ignition systems are tested.
Biting the hand that feeds IT
