I have a THOR 45 CDI I bought to replace two that's two bad Supertiger 3250's. I can't get it to run at top RPM for any consitant period. Surging or misfiring at above 6000rpm. Today it ran for about two minutes with out burping or surging. Adjusted the carb ever way possible. Seems to run most consistent at factory setting of 1 1/2 turns high and low needle. Ran good like I said refueled and burp-BurpBurp-Burp again. Any body have experience with this engine.