if you are using the .12ss engine, try going 5 turns out with the black spring. Of course make sure the set screw is on tight. Also I hope your cam is on correctly. That's the thing that the set screw is in. it could very easily be backwards. The way to verify that is to point your car away from you, hold the two speed gear with your finger and roll the front wheels a bit forward until you see the first set screw. if that one is pointing straight up and down, and another screw to the right of it is leaning a little to the right, your cam should be facing correctly. Then you just adjust yuor set screw. Sometimes it could be too loose and you would be shifting waay to early.