Halloo. I'd check the intake manifold seals too. With motor running, spray some WD40 or some spray you can direct (ya know, can with a nozzle tube) at the intake/head junction, and see if the motor speeds up or slows down. Also, don't know if yours has one, but if it uses a vacuum type fuel-cock, you might have a bad diaphragm. Let us know what you find.