Try blocking the choke plates partway closed. If the performance increases and the plugs go tan or at least not pure white, you're definitely lean. Carburetor jets and number drills go together nicely, but you can't "un-drill" one if you get it too rich.
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!