Editing Finding vacuum leaks

Here's the best way I have found to diagnose bad running engine that may have a vacuum leak;
(1) get a soldering Propane tank and valve attachment.
(2) unscrew the end of it so you have a threaded pipe without the nossle
(3) attach a 2 foot piece of hose to the end
(4) start the engine and let it warm up a bit
(5) turn on the propane and run the hose all aroung the vacuum lines and the bottom of the carb too
(6) if the engine smooths out or revs up a bit you have found your leak

PLEASE do this in a well ventilated area due to propane gas and exhaust fumes!!