Three 0.1µF (50V) capacitors must be properly installed on all motors!
Electric motors used for R/C generate radio noise that can interfere with your receiver and cause radio problems. Included in the accessory kit with the speed control are three 0.1µF (50V) non-polarized, ceramic capacitors. These capacitors must be installed on every motor to help reduce the noise generated by the motor and also to prevent possible damage to the speed control.
Solder a 0.1µF (50V) capacitor between each of the following:

*If your motor does not have a ground tab, solder the capacitor leads to the can of the motor as shown below.
IMPORTANT NOTE:
Cracked, damaged, or missing motor capacitors must be replaced to avoid radio interference or possible speed control damage.
Extra 0.1µF capacitors are available in Novak accessory kit #5620