Originally Posted by def
Depends on the material from which the heat shrink is made. Most heat shrink is not good in a fuel environment. You'll need to know the material in order to judge its acceptability in the fuel. I would not use it.
PTFE heat shrink *you'll have to go to an industrial supplier, like McMaster-Carr, to get it* is pretty robust, it wouldn't cost much to run a test of the stuff in a cup of gas.