Check to see if you've got a vacuum passage covered up by the carburetor base gasket. If the power valve doesn't get vacuum, the piston stays down and the power system goes full rich and stays that way. Lots of gas bypasses the main jet and you have the equivalent of running full throttle/low manifold vacuum all the time.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!