How did it run before you took the carb off? Sounds like you might have a gasket leak----to truly adjust jets per reading plugs, must be done ASAP after a load put on the engine. At the drags ,before you get your slip and idle to the pits.That being said, unless mods were made to your engine ,manufacture should have it pretty dialed in....I believe 500' above sea level off the top of my head. You would go up or down 1 jet size based on the altitude you operate in. Also never over look the sticking choke.