Briggs and Stratton running rich.

[gto41]

Mower would not start. Purchased new carburetor from local John Deere parts store. The new carb is a replacement carb for the original and has no mixture adjustment. I can tell the engine is running rich. If I remove the vacuum line from the fuel pump the motor runs great until it runs out of gas. If i pinch the fuel line it runs great until it runs out of gas. any ideas?

 

[ILENGINE]

Make sure the oil isn't contaminated with gas. the fumes can get drawn through the breather system into the intake just below the air filter and cause a rich run situation.