Say Again You are more likely to find a knackered old Continental in a 150 and a knackered old Lycoming in a 152. Not being pedantic but the latter generates carb ice at a reasonable rate, the former generates more carb ice than power at low revs for the reason given be
Max Rate . Most times in a 152 you'll get away with a quick squirt of carb heat on the downwind leg. A 150 on a humid day can generate loads of ice by the end of the downwind leg and needs a good dose of heat to clear it.
As
jezbowman says carb ice can and DOES form on the ground. The pre-takeoff carb heat check isn't just to see if the carb heat is working, it's also to check if you have carb ice!!! If the engine runs rougher than usual, it'll be the carb ice folks. Don't agree with keeping it open on the ground though. Unfiltered air in a dusty environment (or even not so dusty) does terrible things to cylinders and piston rings. Far better to do your checks and then, if you've been sitting for a few minutes, run up to 1500 or so rpm to get some heat into the exhaust and give a quick shot of carb heat. If there is some rough running keep the carb heat on until it clears. If there is nothing more than a slight drop in the rpm you are clear to go
As
Whirly implies, it's not there to decorate the dash panel, USE IT. I seem to recall the CAA saying that carb ice causes more CFIT (controlled flight into terrain) accidents than any other single cause (I stand to be corrected on this).
Don't be confused by the OAT, as
strafer points out it is common in Florida which generally is a tad warmer than Blighty!!
As the air contracts in the carburettor throat the temperature drop can be as much as 50 C. It has to be a VERY warm day for there not to be -ve temperatures in the carb throat. Couple that with a touch of humidity and you have a lovely carb ice cocktail. Unless the carb heat is used, silence WILL eventually ensue (apart from the screams from the left hand seat!).
Ramble mode OFF