part throttle bog/hessitation/backfire

Maybe try taking a heat gun and warming the cr@p out of the bottom of your plenum, then go for a a quick drive.

See if having some heat in the manifold helps, then it may show to be a weather condition.

If the accel pump arm doesn't have some play in it at full depress, it may rupture the diaphram. It leaks outside the carb.