Scott wrote:

OK...but if it was carb ice, would the engine restart immediately after
getting out to hand prop?

Sure...the flow of cooling air would stop, and the carb would quickly
warm up by conduction.

Frank Courtney, in his book "The Eighth Sea," claims to be the
discoverer of carburetor icing...not the first to HAVE carb ice, but the
first to discover what was causing some otherwise-unexplainable engine
failures.

He had been participating in a cross-country race with an engine with an
updraft carb and no air filter. The engine quit, he set the plane down,
and climbed out. He reached the engine just in time to see a chunk of
ice drop out of the carburetor throat.

My "heat muff" is a replica of an Aeronca 7
series heat muff...just an aluminum "cover" that clamps around the "Y"
of the exhaust pipe. Is there an easy way to get more heat such as
wrapping a spring or something around the pipes to get more thermal
mass? Ideas anyone???

IIRC, Tony Bingelis recommends exactly your approach; wrapping
screen-door springs around the pipes. You need more surface area inside
the heat to pick up heat to transfer to the air.

You might ask at the Aeronca Aviators Club forum page...

http://www.aeronca.typeclubs.org/BB3/

....or ping Harry Fenton directly via the links at the start of the page
I previously posted.

Ron Wanttaja