0388544 JOHNSON CARBURETOR ASSY.

Illustration 1 g00444304
System Schematic For An AC Transformer Box (ATB+)A Wye Connection Is Shown For The Generator.
When the engine-generator, or any source to which the engine-generator is synchronized to, is operating, voltages up to 600V are present in the control panel.Do not short these terminal with line voltage to ground with any part of the body or any conductive material. Loss of life or injury could result from electrical shock or injury from molten metal.
Test Step 1. THE PROBLEM IS WITH AC VOLTAGE OR THE PROBLEM IS WITH AC CURRENT.
Determine if the problem is with AC voltage or with AC current. Check the display of the GSC+ while the genset is running and the load is connected.Results:
AC VOLTAGE - Zero volts are showing on the display of the GSC+ for one or more AC phases. Proceed to Test Step 2.
AC CURRENT - Zero amperes are showing on the display of the GSC+ for one or more AC phases. Proceed to Test Step 7.Test Step 2. CHECK THE FUSES.
Check the three fuses on the AC transformer box + (ATB+).Expected Result:The fuses should not be open.Results:
OK - The fuses are not open. Proceed to Test Step 3.
NOT OK - One or more of the fuses are open.Repair: One or more of the fuses are open. Check for a shorted component or damaged wiring. Troubleshoot and repair the problem. See the Generator Set Wiring Diagram in Testing And Adjusting, "Schematics And Wiring Diagrams". After the problem has been repaired, replace the fuses. Stop.Test Step 3. CHECK THE GENERATOR OUTPUT.
Open the circuit breaker or remove the load.
Start the engine and run the genset.
Measure the voltage between all three fuses on the ATB+. Expected Result:The line to line voltage should measure the rated voltage of the genset. Results:
OK - The voltages are correct and the problem remains. Proceed to Test Step 4.
NOT OK - One or more of the voltages are NOT correct.Repair: The wiring or the connections are damaged. Check for damaged wiring between the ATB+ and the bus. See the Generator Set Wiring Diagram in Testing And Adjusting, "Schematics And Wiring Diagrams". Also, check the electrical connections at the terminal of the ATB+. See Testing And Adjusting, "Electrical Connector - Inspect". Stop.Test Step 4. CHECK THE CONNECTIONS
Shut down the engine.
Check the harness connector and the terminals of the ATB+.
Check the GSC+ harness connector. See Testing And Adjusting, "Electrical Connector - Inspect".
Check for one or more damaged wires between the ATB+ and the GSC+. See the Generator Set Wiring Diagram in Testing And Adjusting, "Schematics And Wiring Diagrams".Expected Result:The wiring and the connectors should have been good.Results:
OK - NO problem was found with the connectors or with the wiring. Proceed to Test Step 5.
NOT OK - The problem was with the connectors or with the wiring.Repair: Repair the connectors or replace the wiring harness. Stop.Test Step 5. CHECK THE OUTPUTS OF THE ATB+
Remove the GSC+ harness connector from the ATB+.
At the terminal of the ATB+, measure the resistance between the following terminals: terminal J1-7 to terminal J1-1, terminal J1-7 to terminal J1-2 and terminal J1-7 to terminal J1-3Expected Result:Each of the resistance measurements should be 7.0 1.0 Ohms.Results:
OK - Each of the resistance measurements is 7.0 1.0 Ohms. Proceed to Test Step 6.
NOT OK - One or more of the resistance measurements is NOT 7.0 1.0 Ohms.Repair: The ATB+ has failed. Replace the ATB+. See Testing and Adjusting Section, "EMCP Electronic Control (AC Transformer Box) - Replace". Stop.Test Step 6. CHECK THE INPUTS OF THE ATB+
Remove the three fuses on the ATB+: F11, F12 and F13
At the terminal of the ATB+, measure the resistance between the following terminals: terminal T11 to terminal H21, terminal T12 to terminal H21 and terminal T13 to terminal H21Expected Result:Each of the resistance measurements should be 1,050 100 Ohms.Results:
OK - Each of the resistance measurements is 1,050 100 Ohms.Repair: The GSC+ may have failed. It is unlikely that the GSC+ has failed. Exit this procedure and perform this entire procedure again. If the problem remains, replace the GSC+. See Testing And Adjusting, "EMCP Electronic Control (Generator Set) - Replace". Stop.
NOT OK - One or more of the resistance measurements was NOT 1,050 100 Ohms.Repair: The ATB+ has failed. Replace the ATB+. See Testing and Adjusting Section, "EMCP Electronic Control (AC Transformer Box) - Replace". Stop.Test Step 7. CHECK THE CURRENT TRANSFORMERS
Shut down the engine.
At terminals 51, 52, and 53 of the ATB+, disconnect only the wires that lead away from the ATB+. These disconnected wires go to the current transformers. These current transformers are CT1, CT2, and CT3.
Measure the resistance from terminal 50 to each of the disconnected wires.Expected Result:The resistance should be approximately 5 Ohms.Results:
OK - The resistances are approximately 5 Ohms. Therefore, the current transformers are good. Proceed to Test Step 8.
NOT OK - One or more of the resistance measurements are NOT correct. A related current transformer or related wire is open. Repair: Replace the open current transformer or repair the wiring. See the Generator Set Wiring Diagram in Testing And Adjusting, "Schematics And Wiring Diagrams". Stop.Test Step 8. CHECK THE OUTPUTS OF THE ATB+
Shut down the engine.
Remove the harness connector from the GSC+.
At the harness connector of the GSC+, measure the resistance between the following contacts: contact 4 to contact 16, contact 5 to contact 16 and contact 6 to contact 16. Be sure to allow each measurement to stabilize.Expected Result:Each of the three resistances should be 120 20 Ohms.Results:
OK - Each of the three resistances is 120 20 Ohms. Proceed to Test Step 10.
NOT OK - One or more of the resistance measurements are NOT correct. Proceed to Test Step 9.Test Step 9. CHECK THE GSC+ HARNESS CONNECTOR
Remove the harness of the GSC+ from the ATB+.
Check the resistance of the wires in the harness of the GSC+ for an open wire. See the Generator Set Wiring Diagram in Testing And Adjusting, "Schematics And Wiring Diagrams".Expected Result:The wires in the harness of the GSC+ should measure