.... so the venturi effect is minimised which should lead to less of an adiabatic reduction in temperature however ......icing is more prevalent at low power which is surprising. I think Dubtrub may be right in that the butterfly valve is the restriction that leads to icing at low rpm i.e. the valve has a small aperture leading into the main body of the carb.

happy landings

B

Yup Dubtrub's makes sense. But much of the cooling is due to fuel vapourisation, not just the venturi. As fuel is being vapourised at the same pro-rata rate...