The magnetic speed sensor is mounted in the ring gear case or flywheel bell housing of the engine. The threaded hole for the speed sensor should be perpendicular to the centerline of the crankshaft and centered over the ring gear teeth. A spot face should be present to provide a flat surface on which to anchor the locknut. With the engine stopped, screw the speed senor in until it touches a gear tooth, then back it out 3/4 of a turn and secure it with the locknut. Any ferrous gear may be used as long as the frequency and amplitude of the resulting signal meet the speed control unit specifications

The wire leads should be twisted for their entire length from the magnetic speed sensor to the control unit. The leads may needshielding if they are longer than 10 ft. (3m), or if external interference is present.

Do not connect either of the speed sensor leads to anything but the speed control unit used. The shield should not  be magnetic sensor.