ENGINE AR 4P0844 - Caterpillar

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5N1955 ELECTRONIC SPEED SWITCH
1. Verify button. 2. Reset button. 3. "LED" overspeed light. 4. Seal screw plug (overspeed). 5. Seal screw plug (crank terminate). 6. Seal screw plug (oil step).Overspeed Setting Calibration
1. Remove lockwire and seal from seal screw plugs (4), (5) and (6). Remove seal screw plug (4) from access hole for overspeed adjustment screw.2. Use a small screwdriver and lightly turn overspeed adjustment potentiometer twenty turns in the direction of "MAX ARROW" (clockwise). The overspeed adjustment screw is made so that it can not cause damage to the potentiometer, or be removed, if the adjustment screw is turned too many turns in either direction.3. Run engine at 75% of desired overspeed setting rpm. Make reference to the SPEED SPECIFICATION CHART (Part of PROCEDURE D).4. With engine at 75% of overspeed setting rpm, push VERIFY button (1) and hold in. Turn overspeed adjustment potentiometer in the direction opposite of "MAX ARROW" (counterclockwise) slowly until "LED" overspeed light (3) comes on. Engine will shutdown if speed switch is connected to the fuel shutoff solenoid and/or air inlet shutoff solenoid.5. To reset speed switch, push in reset button (2). Air inlet shutoff must be manually reset.6. Slowly turn overspeed adjustment potentiometer approximately one turn clockwise and do Steps 3, 4 and 5 again. More adjustment may be needed to get the correct setting. Turn adjustment potentiometer clockwise to increase speed setting, and counterclockwise to decrease speed setting. Turn adjustment potentiometer very slowly only a small amount at a time until adjustment is correct.7. When the speed setting is correct, install seal screw plug (4) in overspeed adjustment access hole. Tighten screw to a torque of 0.20 0.03 N m (2 .3 lb.in.). Install the lockwire and seal (if crank termination and oil step adjustments are complete).