.12 mega zx dsii engine problems?
 

I have a mega zx dsii .12 engine in my serpent 1/10 and it starts ok but idles for a couple of seconds then starts screeming! Even when idling before it screems it bogs when trying to rev it? I've tried to take carb out and seal with hylermar instant gasket but no different. Any help would be very apreciated.

richen the bottom end :)