An anti-adjusting rotary valve type carburetor includes a high speed adjustment oil needle having an eccentric hole and an idle adjustment oil needle having an eccentric hole. Also disclosed is a specialized adjustment tool having an eccentric convex platform for adjusting the high speed adjustment oil needle and the idle adjustment oil needle. Also disclosed is a high speed adjustment oil needle having an eccentric convex platform and an idle speed adjustment oil needle having an eccentric convex platform. Also disclosed is a specialized adjustment tool having an eccentric hole for adjusting the high speed adjustment oil needle and the idle speed adjustment oil needle.