Section 6
DIAGNOSTIC TESTS
TEST 5 - CHECK STEPPER MOTOR CONTROL
PROCEDURE:
1.Remove air cleaner cover to access stepper motor.
2.Physically grab the throttle and verify the stepper motor, linkage and throttle do not bind in any way, if any binding is felt repair or replace components as needed. Some resistance should be felt as the stepper motor moves through it's travel.
3.Physically move the throttle to the closed position by pushing the throttle down as looking from above.
a.Place the idle control switch to off.
b.Place the start switch to start and watch for stepper motor movement it should move to the wide open position during cranking. Once the unit starts the stepper motor should move the throttle to a position to maintain 60 Hertz.
STEPPER
MOTOR
LINKAGE
THROTTLE
Figure 6-2. – Stepper Motor, Linkage and Throttle
Seen From Above
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FULL THROTTLE |
| CLOSED THROTTLE | ||||||
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5.If problem continues remove six pin connector from printed cir- cuit board. Set Volt meter to measure ohms. Carefully measure from the end of the six pin harness as follows:
BLACK
BROWN
ORANGE
YELLOW
RED
EMPTY
Figure 6-4. – Six Pin Connector Wire Colors
NOTE: Press down with the meter leads on the connectors exposed terminals, do not probe into the connector.
a. Connect one meter lead to Red, connect the remaining test lead to Orange, approximately 10 ohms should be measured.
b. Connect one meter lead to Red, connect the remaining test lead to Yellow, approximately 10 ohms should be measured.
c. Connect one meter lead to Red, connect the remaining test lead to Brown, approximately 10 ohms should be measured.
d. Connect one meter lead to Red, connect the remaining test lead to Black, approximately 10 ohms should be measured.
e. Connect one meter lead to Red, connect the remaining test to the stepper motor case. No resistance should be measured INFINITY or Open”
See Figure
6.Set a voltmeter to measure DC voltage.
7.Connect the positive meter test lead to Wire 15B at Terminal Block 1 (TB1). Connect the negative meter test lead to ground. See Figure
8.Set a voltmeter to measure resistance.
Figure | 9. Disconnect the J2 connector from the printed circuit board. | |
4. If no movement is seen in Step 3 remove the control panel | Connect one meter test lead to Pin Location | |
Connect the other meter test lead to Wire 15B at Terminal | ||
cover. Verify the six pin connector on the printed circuit board is | ||
Block 1 (TB1). See Figure | ||
seated properly, remove the connector and then replace it and | ||
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test again. Verify the switches are correctly set. See Figure |
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on Page 16 for positioning. |
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Page 40