MISSING AT HIGH SPEED
If an engine runs well at low speed, but misses when speeded up, the trouble may be due to weak battery, stuck vibrator blade, or loose connections. A battery that will produce a good spark at low engine speed may not be able to respond to the greatly increased demands of high speed, and similarly, at low speed the period during which the timer holds the circuit closed is longer than at high speed, and the vibrator has more time to get into action before the circuit is broken. A loose connection may be so shaken by the vibrations of high speed as to break the circuit.