Cummins/Onan C8.3 Engine

⚠ Be sure to disengage the engine timing pin after locating top dead center to prevent damage to the engine timing pin.

Tools: Engine barring gear, Feeler gauge

1. Remove the air crossover tube, support clamps, hose clamp, and wastegate sensing line.
2. Remove the crankcase vent tube and remove the valve cover.
3. Locate top dead center for cylinder No. 1 by rotating the crankshaft while pressing on the engine timing pin.
4. Check/adjust the valves indicated for STEP A (I = intake; E = exhaust).
5. Tighten the rocker lever locknut and recheck valve clearance. Torque: 24 N•m [212 in-lb].
6. Disengage the timing pin; mark the vibration damper and rotate the crankshaft 360 degrees.
7. Set the valves indicated for STEP B; tighten the locknut and recheck the clearance.
8. Install a new rubber seal in the valve cover and new sealing o-rings on the capscrews.
9. Install the valve cover, wastegate sensing tube, and crankcase vent tube.

⚠ The maximum engine speed should only be altered by a Cummins technician.

1. Start the engine.
2. Observe that the engine accelerates to the currently adjusted speed setpoint.
3. Locate the threaded linkage rod on the fuel pump side of the engine.
4. Loosen the locking nuts against the stops on the threaded rod.
5. To increase speed, turn the bolt on the right side of the throttle bracket clockwise.
6. To decrease speed, turn the bolt counter-clockwise.
7. When the rated speed is correct, tighten the locking nut against the stop.
8. Adjust the left-side threaded bolt for maximum speed if needed.
9. Stop the engine and repeat until the desired speed is attained.

⚠ Do not exceed 120% of rated speed.

Tools: Signal generator (0.25 to 120 VAC RMS)

1. Lower the cover on the engine's local control panel.
2. Disconnect the engine speed sensor signal from PICK-UP terminals 1 and 2.
3. Connect a signal generator capable of providing 0.25 to 120 VAC RMS proportional to the engine's rated speed.
4. Remove the calibrating screw cover from the electronic overspeed switch.
5. Turn the potentiometer screw clockwise to increase trip speed, counter-clockwise to reduce trip speed.
6. Adjust until the OVERSPEED light is just illuminated at the desired setpoint.
7. Replace the screw cover, disconnect the signal generator, reset the light, and reconnect the speed sensor input.

⚠ Batteries can emit explosive gases. Always ventilate the compartment before servicing the batteries.

⚠ Acid is extremely dangerous.

Tools: Hydrometer, Refractometer

1. Use a hydrometer to measure the specific gravity of each cell.
2. Check the battery fluid column in the refractometer to determine the state of charge of each battery cell.
3. If charge is low, charge the batteries.
4. Replace the battery if it will not charge to the manufacturer's specifications.

⚠ If leakage is detected, the heat exchanger must be replaced.

Tools: 1-1/4" NPT pipe plug, 700 kPa [100 psi] pressure gauge

1. Install a 1-1/4" NPT pipe plug at the raw water outlet of the heat exchanger.
2. Install a pressure test setup with a 700 kPa [100 psi] pressure gauge at the 1" NPT raw water inlet.
3. Apply air pressure at 621 kPa [90 psig].
4. Isolate the pressure source and monitor the pressure gauge for 5 minutes.
5. Release the pressure, then remove the pipe plug and the test setup.

⚠ Do not remove the pressure cap from a hot engine.

Tools: Thermocouple or temperature gauge (optional)

1. Start the engine and allow it to approach operating temperature.
2. Monitor the operation of the thermostat; initial opening temperature MIN 81°C [178°F], MAX 83°C [181°F].
3. Stop the engine when the coolant starts to flow.
4. If the coolant does not start flowing in the initial opening range, the thermostat must be replaced.
5. Install the heat exchanger hose and tighten the hose clamp.

1. From the User Interface screen press the MENU soft key.
2. Press the OVERSPEED TEST soft key from the Settings Menu.
3. Press the RUN soft button.
4. When the dialog box appears, proceed with the test and select Yes.
5. When the timer expires, ENGINE OVERSPEED flashing in red appears at the top of the FPDP screen.
6. The engine will enter MANUAL mode until reset.
7. Press the RESET/STOP switch on the FPDP to reset the fire pump drive engine.

Tools: Digital multimeter

1. From the User Interface screen press the MENU soft key.
2. Press the ENGINE SETUP soft key from the Settings menu.
3. Enter password 806 in the Engine Setup Login screen.
4. Press the TERMINAL BLOCKS soft key from the Engine Setup menu.
5. Press the soft key corresponding to the terminal block requiring verification.
6. Press the RETURN soft key to exit the Terminal Block Test menu.

⚠ Battery electrolyte (sulfuric acid) is highly caustic.

⚠ Batteries can emit explosive gases during charging.

⚠ Remove the negative (-) battery cable first and attach it last.

Tools: Neoprene gloves, Safety goggles or full face shield

1. Install the battery cable kit or equivalent customer-supplied wiring.
2. Install battery sets in a well-ventilated or otherwise protected location.
3. Provide adequate room for servicing or replacing the batteries.
4. Locate the batteries near the engine or increase conductor size as required.
5. Check the battery cables and connections.
6. Coat the terminals with petroleum jelly to prevent corrosion.

⚠ The cooling water supply must be immediately available when the engine is started.

⚠ Do not operate without a pressure cap.

Tools: Appropriate-sized container

1. Provide a cooling water discharge line at the heat exchanger outlet and a supply line to the cooling water inlet.
2. Check the pressure regulator setting on the cooling loop with water flowing through the heat exchanger.
3. Adjust the cooling water based on water flow rather than water pressure.
4. Measure the water flow using a container and elapsed time.
5. Adjust both pressure regulators to provide flow at or above specifications.

⚠ Do not use the engine lifting points for assembly!

Tools: Lifting device, Grease gun

1. Ensure the engine and pump are correctly aligned.
2. Verify engine position centered on frame side to side within +/- .76 mm (.03 in).
3. Align engine center line to pump center line within +/- .76 mm (.03 in).
4. Ensure pump center line to engine crankshaft center line (vertical) is 2 degrees +/- 1 degree.
5. Ensure drive shaft mounting flanges are parallel.
6. Lubricate the grease fittings on the drive shaft universal joint.
7. Check engine is installed per pump manufacturer's specifications.

⚠ Do not use copper or galvanized pipe for the fuel return or supply lines.

⚠ Do not mix gasoline, alcohol, gasohol, ethanol, or methanol with diesel fuel.

Tools: Container for contaminated fuel

1. Install an elevated no. 2 diesel fuel tank or equivalent compatible with ASTM no. 2 diesel specifications.
2. Size the fuel tank for the maximum expected full-load operation period.
3. Install a fuel return line routed to the bottom of the fuel tank.
4. Install a fuel supply line to the fire pump drive engine.
5. Open the fuel filter/water separator drain and drain until no water is present.