Checking for vacumm leak

got this from hrk.....


Or a small propane tank, do not light it but warm up the engine
and set the throttle stop to hold RPM about 1500 to 1700.

Then open up the propane torch but don't light and hold it in around the front flange
and then the rear, if the idle changes you have found that it has a leak.

Also check the vac lines from the manifold, it gets hot in there, things have a habit of
going south in the heat...

Propane makes less of a mess but WD-40 or carb cleaner will do it as well..

good info , thanks for posting it