Generac NP66G Generator Set

Tools: ruler

1. Adjust the spring on four stator can bolts to a length of 13mm (1/2 inch).
2. Adjust two sets of springs on the side of the generator to a length of 16mm (5/8 inch).
3. This will provide proper belt tension.

Tools: screwdriver

1. To adjust choke solenoid: push choke solenoid plunger in until it bottoms out. With plunger bottomed, carburetor choke plate should be closed. If not fully closed, loosen two solenoid screws and repos
2. To adjust choke heater: with engine cold and solenoid NOT actuated, check position of carburetor choke plate. Choke plate should be 1/8 inch from its full open position. If off by a small amount, bend
3. Observe automatic choke operation while cranking the engine. Choke solenoid should energize and choke plate should close for about 0.2 to 0.4 seconds. It should then de-energize and choke plate should

Tools: screwdriver

1. To adjust idle mixture, turn the idle mixture screw clockwise until it just seats.
2. Then, turn the screw counterclockwise 1-1/4 turns.
3. There is no main jet adjustment. That jet is fixed and tested up to 8000 feet altitude.

Tools: screwdriver, frequency meter, tachometer

1. Visually inspect the anti-lash spring. Make sure it is not broken or disengaged. Spring ends must be hooked into governor lever and into carburetor throttle lever.
2. Loosen the governor clamp nut. Hold the governor lever in its wide open throttle position, then use a screwdriver to rotate the governor shaft fully counterclockwise. Hold this position and tighten th
3. Start the engine, let it stabilize and warm up. Both line breakers should be set to their "Off" or "Open" position.
4. Turn the adjuster nut to obtain a frequency reading of 62 Hz. If a tachometer is used, set engine speed: NP45G=2160 rpm, NP55G=2571 rpm, NP65G=2805 rpm, NP52G=2300 rpm, NP66G=2700 rpm, NP72G=2900 rpm.
5. Determine if the governor spring is properly located in the notched teeth of the governor adjustment bracket. If droop is excessive, move the governor spring to the left. For greater stability, move t
6. After repositioning the governor spring, recheck frequency (or rpm) and, if necessary, readjust the adjuster nut to 62 Hertz or to the correct engine speed.

Tools: feeler gauge, shim stock, screwdriver

1. Set spark plug gap to 0.030 inch.
2. Place a piece of 0.008-0.010 shim stock between the ignition module (or armature) and the flywheel.
3. Loosen mounting screws and let the magnet pull the armature down against the shim stock.
4. Tighten both mounting screws.
5. Rotate the flywheel to remove shim stock.

Tools: feeler gauge, screwdriver, torque wrench

1. Remove the valve covers.
2. Turn the crankshaft until piston in cylinder being checked is at top dead center (TDC) of its compression stroke.
3. Insert a screwdriver through spark plug hole so that it contacts the piston. Turn the crankshaft past top dead center until piston has moved downward 1/4 inch (6.35mm).
4. Insert a feeler gauge between valve stem and rocker arm. Clearance should be 0.004-0.006 inch (0.10-0.16mm). Adjust clearance as required until correct.
5. When clearance is correct, hold the adjusting screw and tighten locknut to 60 inch-pounds torque.
6. Recheck valve clearance and readjust if needed.

⚠ Electrical hazard: ensure power is disconnected before working on connections.

1. Gain access to generator panel interior by removing generator cover and front panel.
2. Locate stator leads 11 and 33 that connect to circuit breakers CB1 and CB2. Also locate leads T1 (red) and T3 (black). Disconnect all of these leads from the two circuit breakers.
3. Set aside the red (T1) and the black (T3) wires for later use.
4. Disconnect stator leads 22 and 44 from the grounding terminal (GT).
5. Disconnect one of the two white (T2) leads that attach to the grounding terminal (GT).
6. Install new breakers or, if existing breakers are both rated 30 amps, modify them by installing a rod or bolt between the two breaker handles. Both breakers must operate simultaneously.
7. Connect stator a-c output leads 11 and 44 to the 2-pole circuit breaker as shown. Attach leads T1 (red) and T3 (black) to the circuit breaker. Connect stator a-c output leads 22 and 33 together. From
8. Reassemble the panel and generator cover after all connections are completed.

1. Check air inlet and outlet openings for sufficient cooling and ventilating air flow.
2. Inspect wiring connections for code compliance and safety.
3. Check the generator exhaust system. Never operate a generator having defective exhaust piping or muffler.
4. Inspect the engine-generator assembly. Never operate a damaged or defective unit.
5. Check engine oil level and make sure an adequate supply of the proper fuel is available.

1. Set the line breaker(s) to their "Off" or "Open" position.
2. Hold the start/stop switch at "Start" to crank and start engine. Release when engine starts.
3. Connect the generator a-c output to the vehicle load circuits.
4. Let the generator engine stabilize and warm up.
5. Set the line breaker(s) to their "On" or "Closed" position.

1. Set the line breaker(s) to "Off" or "Open".
2. Let the engine run at no-load for a minute or two, to stabilize internal temperatures.
3. Hold the start/stop switch at "Stop". Wait for engine to come to a complete stop.