Cummins/Onan 10CW-150R Generator Set

Tools: 8 penny nail or 1/8 inch rod

1. Loosen carburetor choke arm on its shaft.
2. Slip choke assembly cover upward to remove it.
3. Insert an 8 penny nail or 1/8 inch rod through aligning holes of solenoid armature and core.
4. Tie armature firmly against core.
5. Set choke valve plate fully closed and tighten choke arm on shaft.
6. Remove alignment nail and untie armature; replace cover.

⚠ Do not turn too far; a few degrees are usually sufficient.

1. If choke does not open as engine warms up, check electric heating element.
2. Loosen choke housing clamp screw.
3. Turn housing slightly counterclockwise for over-choking in cold temperatures.
4. Turn housing slightly clockwise to increase choking in high temperatures.
5. Retighten clamp screw.

⚠ Factory carburetor adjustments should not be disturbed.

Tools: voltmeter

1. Allow engine to thoroughly warm up.
2. Adjust idle with no load: turn idle out until speed or voltage drops slightly, then in to normal.
3. Adjust main with full load: turn main in until speed or voltage drops, then out to normal.
4. For gas carburetor, set idle screw inward to seat; turn main gas screw in until drop, then out to normal.
5. Set lock nut securely.
6. Adjust throttle lever stop screw for 1/32 inch clearance.

⚠ Binding, sticking or excessive looseness in governor travel causes erratic governor action.

Tools: Voltmeter, Frequency meter

1. With plant stopped, set carburetor stop lever clearance to approximately 1/32 inch by turning ball joint on link.
2. Pull governor arm gently toward front of engine; travel must be smooth.
3. Start plant and run at light load until thoroughly warm.
4. Connect voltmeter and/or frequency meter to generator output and adjust for correct speed.

Tools: voltmeter, frequency meter

1. Disconnect booster external spring.
2. At no load, adjust speed nut for 60-61 cycles (60 cycle) or 50-51 cycles (50 cycle).
3. Apply full load; adjust sensitivity for maximum 3 cycle spread.
4. Connect booster external spring at no load with no tension.
5. Apply full load; frequency should stabilize 1 to 2 cycles higher than no load.
6. Adjust internal spring tension if rise more than 2 cycles or if frequency drops.

Tools: voltmeter, frequency meter

1. Check throttle stop lever clearance approximately 1/32 inch.
2. Start and run at light load to thoroughly warm up.
3. At no load, turn speed adjusting nut for 60-63 cycles (60 cycle plant) or 50-53 cycles (50 cycle).
4. Apply full load; governor should keep frequency spread within 3 cycles.
5. If spread more than 3 cycles, turn sensitivity screw clockwise half turn and compensate with speed nut.
6. Check performance under various loads.

1. Remove magneto end cap.
2. Adjust breaker points to .015-inch gap.
3. Remove air cover from right hand cylinder.
4. Slowly turn engine until IMP mark centers in timing hole.
5. Listen for sharp click from magneto.
6. If click before mark, timing fast; if after, slow.
7. Loosen magneto mounting screws and turn magneto to advance or retard.
8. Repeat until proper timing attained.

Tools: Hand crank, Feeler gauge

1. Remove end cap from magneto.
2. Adjust magneto breaker points to a gap of .015-inch at full separation.
3. Remove air cover from right hand cylinder to expose flywheel housing timing hole.
4. Slowly turn engine until IGN timing mark centers in timing hole; a sharp click should be heard.
5. If click occurs before or after mark, loosen two magneto mounting screws and turn magneto slightly.

Tools: hand crank

1. Remove magneto end cap.
2. Adjust breaker points to 0.020 inch gap at full separation.
3. Remove right hand cylinder air cover to expose timing hole.
4. Slowly turn engine until IMP mark centers in timing hole.
5. Listen for sharp click from magneto impulse coupling at the mark.
6. If click is early (fast) or late (slow), loosen magneto mounting screws and turn magneto slightly.
7. Repeat until proper timing is attained.

⚠ Booster cannot compensate for loss of engine vacuum from leaky valves or worn piston rings.

1. Connect booster external spring to bracket on governor link.
2. At no load, slide bracket to position where external spring has no tension.
3. Apply full rated load and check output voltage stability.
4. Lessen internal spring tension if frequency rise exceeds 2 cycles; increase if frequency dips.

⚠ Tappets set too close may cause burned or warped valves.

Tools: feeler gauge

1. Remove valve compartment covers.
2. Hand crank engine until tappet being checked is on low point of cam lobe.
3. Check clearance for intake and exhaust valves.
4. Adjust to 0.012 inch cold at room temperature.
5. Reinstall covers.

Tools: test lamp set

1. For 120/240-volt single phase, contact test leads to the two collector rings nearest the ball bearing.
2. If the lamp fails to light, an open circuit in that winding is indicated.
3. Repeat contacting the two collector rings nearest the commutator.
4. If the test is made between the two middle rings, the lamp should not glow.
5. If it glows, a short between the two windings is indicated.