Cummins/Onan E125H/E140H Engine

Tools: feeler gauge

1. Engine must be at room temperature.
2. Remove the valve rocker cover and spark plug.
3. Turn engine over until piston is at COMPRESSION TOP DEAD CENTER.
4. Check intake and exhaust valve lash with a feeler gauge.
5. Loosen locknut and turn lash adjusting screw until specified lash obtained.
6. Tighten locknut and recheck lash.

⚠ Adjusting engine speed above equipment manufacturer specification may violate Federal and State safety standards.

Tools: accurate tachometer

1. Start engine and move throttle lever to lowest speed position.
2. Adjust low-idle speed stop screw on carburetor to specified low-idle speed.
3. Move throttle lever to highest speed position.
4. Loosen high-idle stop plate clamping screw and rotate plate to specified speed; retighten.
5. For lever controlled engines adjust lever stop screw instead.
6. Check full smooth movement of throttle control arm between stop positions.

⚠ Disconnect spark plug and battery negative cable before adjusting the governor.

1. Loosely assemble governor arm to governor shaft and start the lock nut.
2. Re-attach link to governor arm and carburetor; replace worn clips.
3. Push top of governor arm toward carburetor until it stops and hold.
4. Check governor spring pulls carburetor throttle to wide open.
5. Tighten lock nut; ensure governor shaft rotates clockwise against internal parts.
6. Tighten to Section 3 torque specifications.

⚠ Accidental starting can cause severe personal injury or death.

1. Stop engine and disconnect spark plug and battery negative cable.
2. Push choke knob to full open-choke; set throttle lever to lowest speed.
3. Loosen cable clamp at engine bracket if necessary.
4. Hook cable wires into hook holes in choke and throttle control arms.
5. Rotate control arms clockwise, hold against stops, pull out cable slack, tighten clamp.
6. Check smooth movement and full travel of choke knob and throttle lever.
7. Reassemble air cleaner and reconnect spark plug and battery.

⚠ Reversed battery connections or operation without a battery will damage the voltage regulator and/or alternator stator.

Tools: multimeter (Simpson 270)

1. Check battery voltage with engine not running; charge if out of specification.
2. With engine running, check voltage regulator output at battery terminals.
3. Disconnect stator leads from regulator and test stator AC output.
4. Shut down engine and check resistance between each stator lead and ground.
5. Check stator resistance across stator leads with ohmmeter.
6. Replace stator if resistance out of specification.
7. Replace flywheel assembly if stator resistance is correct but output low.

1. Pull choke knob to full-choke position to close choke plate.
2. Remove outer cover; wipe away loose dust and debris.
3. Remove mounting nut, inner cover and air cleaner element.
4. Wipe dust and debris from the air cleaner base.
5. Install new paper element and secure with inner cover and mounting nut.
6. Tighten nut 1-1/2 turns after seating it on the cover.
7. Reinstall foam wrapper and outer cover.

⚠ Failure to adequately wring out excess oil from wrapper may cause a drop in engine power due to restriction of inlet air.

⚠ Replace foam wrapper when torn or stretched.

1. Remove outer cover by rotating quarter-turn fastener counterclockwise, then lift cover.
2. To service foam wrapper only, do not remove inner air cleaner cover. Remove and wash foam wrapper in water and detergent.
3. Squeeze foam wrapper dry like a sponge. Rinse with clean water and allow to dry.
4. Coat wrapper evenly with one tablespoon (14 grams) of SAE 30 engine oil. Knead oil in and wring out excess.
5. Install foam wrapper over paper air cleaner element by stretching it over inner cover. Completely cover all exposed paper pleats.
6. For element replacement: pull choke knob to full-choke to close choke plate. Remove outer cover and wipe away loose dust.
7. Remove mounting nut, inner cover and air cleaner element. Wipe off dust from air cleaner base.
8. Install new paper element and secure with inner cover and mounting nut. Tighten nut 1-1/2 turns after seating it on cover.
9. Reinstall foam wrapper and outer cover.

⚠ Always wear safety glasses when using compressed air or pressure washer to avoid severe eye damage.

Tools: Compressed air, Pressure washer

1. Wear safety glasses.
2. Let engine cool, especially when using pressure washer. Temperature stresses from cleaning hot engine can crack cylinder.
3. Use compressed air or pressure washer to clean cylinder cooling fins.
4. Observe all manufacturer's instructions and precautions when using pressure washer.

1. Operate equipment as intended for first 1-1/2 hours at about half available engine power, occasionally full power briefly. Avoid prolonged low-speed, low-power operation.
2. Use proper engine oil for ambient temperatures during break-in. Change oil if not appropriate.
3. Check oil level twice a day or after every 4 hours during first 24 hours.
4. Change oil and oil filter after first 24 hours and have valves readjusted by qualified mechanic.

⚠ Accidental starting can cause severe injury or death. Disconnect spark plug and battery before changing oil.

⚠ Crankcase pressure can blow hot oil out fill opening causing severe burns. Stop engine before removing oil fill cap.

⚠ Too much oil can cause high oil consumption, high operating temperatures and oil foaming. Too little oil can cause severe engine damage. Keep oil level between Full and Add marks.

1. Run engine until warm. Stop engine and disconnect spark plug and battery (negative cable).
2. Remove oil fill cap.
3. Place pan under oil drain opening and remove oil drain plug. Reinstall plug securely after oil drains.
4. Spin off oil filter canister, drain oil and discard filter according to local regulations.
5. Wipe off filter mounting surface.
6. Make sure gasket is in place on new filter canister and apply thin film of oil to gasket.
7. Spin on new filter canister by hand until gasket touches mounting pad, then turn additional 1/2 to 3/4 turn. Do not overtighten.
8. Refill with API Class SG or SH oil (also SG/CD, SG/CE, SH/CD or SH/CE) having SAE viscosity appropriate for expected temperatures. See Table 1. See Specifications for oil capacity.
9. Reconnect spark plug and battery.
10. Start engine and run briefly, checking for oil leaks around drain plug and oil filter.
11. Pour used oil into sealed container and deliver to recycling center.

⚠ Failure to wring out excess oil may cause a drop in engine power.

1. Do not remove the inner air cleaner cover.
2. Remove and wash foam wrapper in water and detergent.
3. Squeeze foam wrapper dry like a sponge.
4. Rinse with clean water and allow to dry.
5. Coat wrapper evenly with one tablespoon (14 grams) SAE 30 engine oil.
6. Knead oil into the wrapper and wring out excess oil.
7. Install wrapper over paper element, covering all exposed pleats.

⚠ Gasoline is highly flammable and can cause severe personal injury or death. Let engine cool and close fuel shutoff valve before disconnecting fuel line. Do not smoke or use open flame near engine or fuel tank.

1. Allow engine to cool before disconnecting fuel line so it cannot ignite spilled fuel.
2. Close any shutoff valve in fuel line.
3. If filter is in-line type, loosen inlet and outlet hose clamps to remove.
4. Replace filter and secure connections.
5. Check for leaks.