Start by changing the fuel filter, particularly if it's one of those small ones at the carburetor inlet fitting. They're notorious for getting clogged up just enough to restrict the fuel flow at or near full throttle.
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!