Unscrew the burner tip from the brass torch pipe and slip on a long length of vac hose. Then you can fish the end of rubber hose all around real easy. Just crack the torch valve till you hear a slight hiss....The engine will smooth out when you find the vac leak.

Attach a piece of stiff wire to end of hose (tape it on) to reach hard to get to stuff. Bend wire as needed...