AIr leaks

[clemsonhacker]

What are the most common places for a leak?

 

[nitrogator]

fuel lines and tank but there are lots of places to leak

 

[jetmechG550]

Base of the carb and the backplate.

 

[joneser4u]

front bearing if its gone bad.

 

[HeartBreak]

Or your glow plug shim. I've also seen screw holes for the backplate punched all the way through, causing an air leak. Tiny cracks in the crank case... Could be anywhere.

My favorite method of chasing airleaks (at least BIG ones), is to fill the engine with after run oil, and pressurize the engine with canned air (GENTLY!). The oil will follow the air and leak out. I've used this trick to find bad carb seals, cracks, and loose heads. Your mileage, however, may vary.