Carb Ice on 180 hp

[andy]

Only experienced carb ice 2 times in 900+ hours in my MX-7-180. Both times humidity was high and temperature was in the 40s. First time was on takeoff. Engine surged and ran rough until carb heat applied. Second time in cruise at 2200 MSL, 21" MP and 2300 RPM. Noticed gradual drop in manifold pressure. Applied full carb heat and manifold pressure increased to normal.

Andy

[a64pilot]

How do you teflon coat the inside of a carb?

[210TC]

Remove the butterfly and the shaft will come out then send them out to be coated.
If your shaft is slopy have the full lenght of the shaft coated to take up some of the clearence.
The problem is ice attaches to the butterfly (not the inside surface of the carb). I think you could just get away with coating the butterfly. I would have both done.
Another thought would be to purchase these parts new and have them coated then install at annual. You would need new screws anyway (the two that lock in the butterfly).
The bigest problem would be locating a company that would coat these parts in a uniform mannor.