Originally Posted by JOHN TAN
oh i never noticed that just keep tuning till it can run at reasonable speed in the circuit but the low speed screw head is about flush with the needle while the high speed is between 2.5~3 turn lean out...but overall i can't lean it anymore as I almost saw the engine is too hot to be lean further...top speed is very slow maybe like 50km/hr only...
Could be an airleak, i had to replace the orings in my hyper .12 carb the other day, i had the same symptons, overheating loss of power and not very good speed it was also taking a while for the revs to drop after WOT, replaced orings in carb sealed engine with RTV sealant and its good as new (well it is actually also replaced piston / sleeve / rod) but did the carb first to test and it was the cause. hope this helps, Happy new Year