Cummins/Onan B4.5 Generator Set

Tools: Feeler gauge, Engine Barring Tool, Part Number 3824591, Screwdriver or Allen wrench

1. Remove the rocker lever covers.
2. Locate top dead center (TDC) for cylinder number 1.
3. Rotate the engine clockwise until cylinder 4 (4-cylinder) or cylinder 6 (6-cylinder) intake rocker arm starts to open the intake valve.
4. Adjust only the valves indicated, holding the locknut steady with a wrench and turning the screwdriver or Allen wrench.
5. Tighten the locknut and measure the valve lash again.
6. Mark the vibration damper and rotate the crankshaft 360 degrees.
7. Adjust the remaining valves as indicated.
8. Check the rocker lever covers for cracks and install them.

⚠ Secure safety chains on the test plugs to any convenient capscrew on the radiator assembly; this test must not be performed without securely fastened safety chains.

Tools: Pressure gauge and regulated shop air supply, Spray bottle with soapy water, Stopwatch

1. Remove the inlet and outlet hoses from the cooler.
2. Install a plug or cap over the outlet side of the cooler.
3. Install a pressure gauge and a regulated shop air supply line with a shutoff valve to the inlet side.
4. Apply air pressure until the pressure gauge reads a steady 207 kPa [30 psi].
5. Shut off the airflow and start a stopwatch; record the leakage at 15 seconds.
6. If the pressure drop is 34 kPa [5 psi] or less in 15 seconds, the cooler is operational.
7. If greater, check all connections with soapy water and repair or replace as necessary.

⚠ Do not remove the pressure cap from a hot engine; wait until coolant temperature is below 50°C [120°F].

⚠ Coolant is toxic; keep away from children and pets and dispose of in accordance with local environmental regulations.

⚠ Never use water alone for coolant.

Tools: Drain pan with a capacity of 19 liters [5 gal]

1. Open the drain valve on the radiator and remove the plug in the bottom of the water inlet.
2. Check for damaged hoses and loose or damaged hose clamps; replace as required.
3. Fill the system with a mixture of sodium carbonate and water and operate the engine 5 minutes above 80°C [176°F].
4. Shut the engine off and drain the cooling system.
5. Fill the cooling system with clean water and operate the engine 5 minutes above 80°C [176°F].
6. Shut the engine off and drain; repeat until the drained water is clean.
7. Fill with a 50-percent water and 50-percent ethylene glycol or propylene glycol antifreeze mixture.
8. Install the pressure cap.
9. Operate the engine until it reaches 80°C [180°F] and check for coolant leaks.

⚠ Drain the fuel-water separator into a container and dispose of contents in accordance with local environmental regulations.

Tools: Crescent wrench (if lid can not be removed by hand)

1. Lift up on the filter drain lever to drain fuel for approximately 5 seconds.
2. Clean all debris from around the canister lid.
3. Remove the filter lid and filter element.
4. Install the new element in the canister lid and replace the o-ring.
5. Lubricate the o-ring with clean engine oil.
6. Place the lid back in the canister by twisting clockwise and hand-tighten the lid.
7. Open the bleed screw and operate the hand lever until fuel is free of air, then tighten the bleed screw.

⚠ Mechanical overtightening will distort threads, filter element seal, or filter can.

1. Use the filter drain valve to drain fuel out of the filter for approximately 5 seconds.
2. Clean the area around the fuel filter head.
3. Remove the fuel filter.
4. Lubricate the o-ring seal with clean lubricating oil.
5. Install the filter as specified by the filter manufacturer.
6. Open the bleed screw and operate the hand lever until fuel is free of air, then tighten the bleed screw.

⚠ Used engine oil can be carcinogenic; avoid inhalation of vapors, ingestion, and prolonged contact.

⚠ Avoid direct contact of hot oil with your skin.

Tools: Container that can hold at least 26 liters [27 qt] of lubricating oil, Oil filter wrench

1. Operate the engine until water temperature reaches 60°C [140°F] and shut it off.
2. Remove the oil drain plug from the bottom of the lubricating oil pan.
3. Clean the area around the oil filter head and remove the oil filter.
4. Clean the gasket surface of the filter head and make sure the o-ring is removed.
5. Fill the new filter with clean lubricating oil and apply a light film of oil to the gasket sealing surface.
6. Install the filter as specified by the filter manufacturer.
7. Check the oil drain plug threads and install the drain plug.
8. Fill the engine with clean lubricating oil to the proper level.
9. Operate the engine and check for leaks at the filters and oil drain plug.

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

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

1. When using jumper cables, connect the cables in parallel: positive (+) to positive (+) and negative (-) to negative (-).
2. When using an external electrical source, turn the disconnect switch to OFF and remove the key before attaching the jumper cables.
3. Do not connect jumper starting or battery charging cables to any fuel system or electronic component.

⚠ Do not depress the accelerator pedal or move the accelerator lever from idle while cranking; this can cause engine overspeed and severe damage.

1. Disengage the driven unit or put the transmission in neutral.
2. With the accelerator in idle position turn the keyswitch ON and wait for the WAIT-TO-START lamp to go out.
3. Turn the key to START.
4. If the engine does not start after three attempts, check the fuel supply system.
5. Idle the engine 3 to 5 minutes before operating with a load.
6. After starting a cold engine, increase engine speed slowly to allow oil pressure to stabilize.
7. Do not operate the engine at low idle for long periods with coolant temperature below the minimum specification.

1. Disconnect the electrical wire from the fuel pump solenoid.
2. Rotate the crankshaft, using the starting motor, until oil pressure appears on the gauge or the warning lamp goes out.
3. Connect the electrical wire to the fuel pump solenoid valve.
4. Start the engine; refer to normal starting procedures.

⚠ The belt tensioner is spring-loaded and must be pivoted away from the drive belt; pivoting in the wrong direction can damage the belt tensioner.

⚠ Applying excessive force opposite the windup direction can break the tensioner arm.

1. Lift the tensioner to remove the drive belt.
2. Inspect the drive belt for cracks, glazing, tears or cuts, hardening, and excessive wear.
3. Lift the tensioner to install the drive belt.