Generac NP-30G Generator Set

⚠ Engine should be at room temperature with piston at TDC of compression stroke

Tools: Allen wrench, Feeler gauge, Crows foot

1. Loosen the rocker arm jam nut.
2. Use an allen wrench to turn the pivot ball stud while checking clearance with a feeler gauge.
3. When clearance is correct, hold the pivot ball stud and tighten the rocker arm jam nut with a crows foot.
4. Tighten the jam nut to 65-85 inch-pounds torque.
5. Recheck valve clearance to make sure it did not change.

⚠ Do NOT adjust the fuel-air mixture excessively lean; can result in engine damage.

1. Turn the idle jet inward (clockwise) until it just contacts its seat; do not force.
2. Turn the idle jet outward (counterclockwise) 1-1/8 turns.
3. Start engine and let it warm up about five minutes.
4. With engine at no-load, turn idle jet clockwise (leaner) until speed decreases or fluctuates.
5. Turn idle jet counterclockwise (richer) until speed decreases/fluctuates or black smoke appears.
6. Very slowly turn idle jet clockwise until speed just stabilizes or black smoke just stops.

⚠ Do NOT adjust the fuel-air mixture excessively lean. An excessively lean mixture can result in engine damage.

1. Turn the idle jet inward (clockwise) until it just contacts its seat; DO NOT FORCE.
2. Turn the idle jet outward (counterclockwise) 1-1/8 turns to allow the engine to start and warm up.
3. Run the engine at no-load and turn the idle jet clockwise (leaner) until engine speed starts to decrease or fluctuate.
4. Turn the idle jet counterclockwise (richer) until speed decreases/fluctuates or black exhaust smoke appears.
5. Very slowly turn the idle jet clockwise (leaner) until engine speed just stabilizes or black smoke just stops.

⚠ Do not overbend the spring clip or the clip will lose its clamping force

Tools: Pliers

1. Start the generator, then shut it down right away and watch the throttle lever rotate counterclockwise.
2. There should be a gap of 0.003 inch (0.08-0.5mm) between the stop tab and the stop block.
3. With pliers lightly compress the spring clip so the linkage rod slides freely.
4. Rotate the throttle lever to increase or decrease the gap to 0.003 inch clearance.
5. Release spring clip to secure the adjustment.

Tools: Allen wrench, feeler gauge, torque wrench, crow's foot

1. Rotate the crankshaft until the piston is at top dead center (TDC) of its compression stroke; both valves should be closed.
2. Loosen the rocker arm jam nut.
3. Use an Allen wrench to turn the pivot ball stud while checking clearance between rocker arm and valve stem with a feeler gauge.
4. When clearance is correct, hold the pivot ball stud with the Allen wrench while tightening the jam nut with a crow's foot.
5. Recheck the valve clearance after tightening the jam nut.

Tools: spark tester

1. Disconnect the high tension lead from the spark plug.
2. Attach the spark plug high tension lead to the spark tester terminal.
3. Connect the spark tester clamp to the engine cylinder head.
4. Crank the engine rapidly; the engine must be turning at 350 rpm or more.
5. If spark jumps the tester gap, the ignition system is operating satisfactorily.

⚠ All Stator leads must be isolated from other components, especially circuit boards, before performing tests. The high voltages used in testing insulation resistance will damage electronic components.

Tools: Hi-Pot tester or Megohmmeter

1. Disconnect and isolate all Stator leads before starting tests.
2. Connect the ends of all Stator leads together; make sure none touch any terminal or part of the generator.
3. Connect one tester probe to the junction of all Stator leads and the other to a clean frame ground on the Stator.
4. Apply a voltage of 1000 volts for about 1 second.
5. If insulation resistance is low, clean and dry the Stator and repeat the test; if it fails again replace the Stator assembly.

Tools: VOM (volt-ohm-milliammeter)

1. Disconnect Wire 77 at the Battery Charge Rectifier (BCR).
2. Disconnect Stator output Wire 66 at the BCR.
3. Disconnect Wire 55.
4. Set a VOM to Rx1 and zero the meter.
5. Connect the VOM test leads across Wires 77 and 55, then across Wires 66 and 55; note both resistance readings.
6. With the unit running, measure AC voltage at the Wires 66 and 77 terminals; if no AC voltage, an open circuit exists in Wire 66 or 77.
7. With engine running, check for DC voltage between the BCR Wire 55 and frame ground; if AC was present but DC is not, the BCR is defective.

Tools: VOM (volt-ohm-milliammeter)

1. Set a VOM to read battery voltage (12 VDC).
2. Connect the VOM test leads across Wire 14 (Red) at the solenoid and a clean frame ground.
3. Set the fuel primer switch on the generator panel to its ON position.
4. The meter should indicate battery voltage and the solenoid should energize open.
5. If battery voltage is indicated but the solenoid does not energize, replace the lockoff solenoid.
6. If battery voltage is not indicated, a problem exists in the DC control system.

⚠ DO NOT attempt to test the Genistor until ALL leads have been disconnected. It MUST be completely disconnected from the circuit or all test results are invalid.

Tools: VOM (volt-ohm-milliammeter)

1. Disconnect all wires from the Genistor before testing.
2. Set a VOM to a resistance scale allowing 20-60 ohms to be read and zero the meter.
3. Connect one VOM lead to COM and the other to terminals G1, G2, G3 and G4 one at a time; each should read 20-60 ohms.
4. Set the VOM to Rx1; connect across COM terminal and the center screw; should read continuity.
5. Check continuity across each AC1, AC2, SL1 and SL2 screw to its terminal.
6. Set VOM to Rx10,000 or Rx1K; there should be no continuity (infinity) between any of the screws.
7. Replace the Genistor if it fails any of these tests.

⚠ All stator leads must be disconnected and isolated before testing.

Tools: Volt-Ohm-Milliammeter (VOM)

1. Disconnect stator power phase leads AC1, AC2, SL1, SL2 at the Genistor and lead 11 at the main circuit breaker.
2. Isolate all leads and ensure none touch the frame.
3. Set VOM to Rx1 scale and zero the meter.
4. Connect one test lead to lead 11; measure resistance to AC1, AC2, SL1 and SL2 individually.
5. To test short-to-ground, set VOM to Rx10,000 or Rx1K and measure each lead to clean frame ground (should read infinity).
6. Test for shorts between windings by measuring between pairs (PS1-AC1, AC1-77, AC1-TIM1, PS1-TIM1, PS1-77, TIM1-77).

Tools: VOM (volt-ohm-milliammeter)

1. Unplug the Stepper Motor connector from its receptacle on the CCG circuit board.
2. Set a VOM to its Rx1 scale and zero the meter.
3. Connect one probe to the connector pin for the RED wire and the other probe to the ORANGE, YELLOW, BROWN and BLACK pins in turn; each should read 19-21 ohms.
4. To test for a shorted condition, set the VOM to Rx10,000 or Rx1K and zero the meter.
5. Connect one probe to the RED wire connector pin and the other to the Stepper Motor case; meter should read infinity.
6. Replace the Stepper Motor if it fails any part of the test.