Gerard,

 

I believe you have found another example of the notoriously poorly written technical guidance we all suffered through in that era.

 

What the writer said:

 

"the use of carburetor heat in heavy rain is recommended both to prevent build of of carb ice and to avoid engine stoppage"

 

What I'm fairly certain the writer meant to say:

 

"the use of carburetor heat in heavy rain is recommended to prevent the build up of carb ice and possible engine stoppage"

 

The engine stoppage you are meant to avoid would be subsequent to the carb icing you are trying to prevent with carb heat.

 

If there is enough water entering the carb to kill the engine I don't think carb heat is going to help much...

 

Regards,

 

Mark