Cummins/Onan P4500 Generator Set

⚠ Must be done when the engine is cold.

Tools: Feeler gauge

1. Remove rocker arm cover and gasket; replace gasket if damaged.
2. Remove spark plug to ease rotation.
3. Rotate engine to TDC of compression stroke.
4. Confirm both rocker arms loose at TDC; rotate 360 degrees if not.
5. Insert feeler gauge between rocker arm and push rod; check clearance.
6. If needed, hold adjusting nut and loosen jam nut.
7. Turn adjusting nut to obtain correct valve lash.
8. Tighten jam nut to 106 in-lb (12 N.m) while holding adjusting nut.
9. Recheck valve lash after tightening.
10. Repeat for both intake and exhaust valves.
11. Install rocker arm cover, gasket, and spark plug.

⚠ Checking and adjusting valve clearance must be done when the engine is cold

Tools: Feeler gauge, Wrench

1. Turn the generator off and allow the engine to cool for 30 minutes; work on a cold engine.
2. Place the generator on a level surface in a well-ventilated area.
3. Remove the engine service cover.
4. Remove the rocker arm cover and carefully remove the gasket.
5. Remove the spark plug so the engine can be rotated more easily.
6. Pull the recoil handle to rotate the engine to top dead center (TDC).
7. Verify both rocker arms are loose at TDC on the compression stroke; if not, rotate the engine 360 degrees.
8. Insert a feeler gauge between the rocker arm and the valve stem to measure valve clearance.
9. If adjustment is needed, hold the rocker arm pivot and loosen the pivot adjusting nut.
10. Turn the rocker arm pivot to obtain the specified clearance; hold the pivot and re-tighten the nut to the specified torque.
11. Recheck valve clearance and perform the procedure on the other valve if needed.
12. Install the gasket, rocker arm cover, and spark plug.

1. Remove the fuel tank.
2. Loosen the nut on the governor arm pinch bolt.
3. Move the arm until the throttle is completely open and hold it in that position.
4. Rotate the governor arm shaft as far as it will go in the same direction and tighten the pinch bolt.
5. Check that the arm and throttle move smoothly.
6. Reinstall the fuel tank.
7. Start the engine and let it warm up; adjust the limiting screw to set the idle speed.

⚠ Checking and adjusting valve clearance must be done when the engine is cold.

Tools: Feeler gauge

1. Remove the rocker arm cover and carefully remove the gasket; replace if torn or damaged.
2. Remove the spark plug so the engine can be rotated more easily.
3. Rotate the engine to top dead center (TDC) by pulling the recoil handle slowly.
4. Verify both rocker arms are loose at TDC on the compression stroke; if not, rotate the engine 360°.
5. Insert a feeler gauge between the rocker arm and valve stem to measure valve clearance.
6. If adjustment is needed, hold the rocker arm pivot and loosen the pivot adjusting nut.
7. Turn the rocker arm pivot to obtain the specified clearance; re-tighten the nut to the specified torque.
8. Perform the procedure for the other valve.
9. Install the gasket, rocker arm cover, and spark plug.

⚠ Valve clearance inspection and adjustment must be performed with the engine cold.

Tools: Feeler gauge

1. Remove the valve cover and set the piston at top dead center of the compression stroke.
2. Insert a feeler gauge between the rocker arm and valve to measure valve clearance.
3. If adjustment is necessary, hold the rocker arm pivot and loosen the pivot lock nut.
4. Turn the rocker arm pivot to obtain the specified clearance.
5. Retighten the lock nut while holding the rocker arm pivot.
6. Recheck valve clearance after tightening the lock nut.

1. Push down the battery access cover tab and pull the cover forward to remove it.
2. Verify the rubber battery strap is firmly securing the battery; hook it onto the mounting base if loose.
3. Remove the cable tie securing the quick-connect battery plugs then push firmly to connect them.
4. Align the tabs on the battery access cover and push to reinstall.

1. Depress the tab on the battery access cover and pull it away from the generator.
2. Verify that the rubber battery strap is firmly securing the battery in place.
3. Remove the cable tie securing the quick-connect plugs then push firmly to connect them.
4. Reinstall the cover.

⚠ This high-altitude kit is to be used at elevations above 2000 feet

⚠ DO NOT operate the generator at altitudes below 2,000 ft (762 m) with the high-altitude kit installed

Tools: Flat head screwdriver, Wrench

1. Remove battery access panel and disconnect the battery.
2. Remove the maintenance panel on the side by removing the 5 bolts that secure it.
3. Remove the control panel by removing the 4 face screws and the two screws on each side; let it hang loose.
4. Drain all the fuel from the carburetor float bowl into a suitable container.
5. Remove the two bolts that secure the air filter box to the carburetor; remove the lid and foam element.
6. Remove the clamp on the vapor tube; remove the vapor tube and crankcase breather.
7. Remove the two nuts that hold the box base to the carburetor and slide it off.
8. Remove the gasket from the carburetor front face; remove the two electrical connections from the stepper motor.
9. Slide the carburetor off the studs and turn it sideways to remove the fuel line.
10. Remove the bolt at the bottom of the float bowl and remove the float bowl.
11. Using a flat head screwdriver, remove the main jet; the jet and emulsion tube will fall out.
12. Install the emulsion tube back into the carburetor with the ridge on top going in first.
13. Select the appropriate jet for your altitude and install it with a flathead screwdriver.
14. Reinstall the float bowl gasket and the float bowl.
15. Reinstall the carburetor, gasket, air filter box, control panel, and side panel; start and verify operation.

⚠ Always connect positive cable first; disconnect negative cable first.

1. Unclip battery access panel on back of unit.
2. Pull down battery strap clip and unhook from mounting base.
3. Lift battery, withdraw bottom-first, stand vertically.
4. Clip battery quick connect to main lead inside inverter.
5. Verify positive cable securely tightened to positive post.
6. Insert battery top-first through access port, stand on mounting base.
7. Check battery positioned correctly, cables not kinked.
8. Pass strap under negative cable and over battery top, hook to base.
9. Replace battery access cover.

⚠ NEVER connect or disconnect the parallel cord leads when a generator is running.

⚠ DO NOT connect two red leads or two black leads into the same generator.

1. Make sure both generator battery switches and ECO MODE switches are in the OFF position.
2. Connect the black and red parallel cable leads to the black parallel ports; black lead to left port, red lead to right port.
3. Connect the green ground lead to the ground terminal on each generator and tighten the nut.
4. Start one generator and wait until the OUTPUT READY LED illuminates.
5. Start the second generator and wait until the OUTPUT READY LED illuminates before connecting a load.
6. Connect additional loads as described in the Power Management section.
7. Unplug all loads before stopping the generators.

1. Turn the generator battery switch to the ON position.
2. Push and hold the ON/OFF button for 10 seconds, then release; the start indicator light will flash green.
3. Push the ON button on the remote start key fob; it will pair automatically and the light will stop flashing.

Tools: Funnel

1. Unclip and remove oil service panel to access oil fill drain plug.
2. Remove oil fill plug and dipstick.
3. Using supplied 4-cycle engine oil and funnel, slowly add oil until full.
4. Do not overfill; oil will drain out through fill plug if too high.