Well someone correct if I'm wrong but I believe the pilot jet is only for idle and low rpm's. So while this may give you trouble at low RPM's you may have a different high rpm problem. I just thought of something else how are the hoses and connections to your secoundary carb doing? Is the diaphram in good shape? Maybe the trouble is in their. If the secondary isn't working properly this would give you high rpm issues. But the rich enviroment is troubling me too.