Cummins/Onan 5CW Generator Set

1. Open adjustments 1 to 1-1/2 turns to permit starting.
2. Warm up engine thoroughly.
3. Adjust idle with no load: turn out until speed drops, then in until normal.
4. Apply full load; adjust main: turn in until speed drops, then out until normal.
5. Ensure governor is properly adjusted.
6. Set throttle stop screw for 1/32-inch clearance.

1. Check carburetor stop lever clearance approximately 1/32 inch.
2. Adjust ball joint on link.
3. Pull governor arm toward front several times; check for binding.
4. Start plant, run at light load to warm up.
5. Make preliminary no-load adjustment for safe voltage.
6. Final adjust governor for rated speed and voltage.

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.

1. Connect booster external spring to bracket on governor link.
2. With no load, slide bracket to position of no tension on external spring.
3. Apply full rated load; output voltage should stabilize.
4. If frequency rise more than 2 cycles, lessen internal spring tension.
5. If frequency dip, increase booster internal spring tension.
6. Clean small hole in short vacuum tube with fine wire.

1. Set tappets for .012 inch clearance intake and exhaust at room temperature.
2. Ensure tappet is on low point of cam lobe.
3. Hand crank engine until valve closes, then one complete turn.
4. Adjust self-locking adjusting screws.

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.

Tools: armature growler

1. An armature growler is required for this test.
2. Follow the test procedure recommended by the growler manufacturer.

Tools: test lamp set

1. Connect one test lamp lead to a bare metal point on the armature shaft.
2. Contact the other test lead to the commutator surface.
3. If the test lamp glows, the dc portion of the armature is grounded.
4. Repeat the test contacting the collector rings.
5. If the lamp glows, the ac portion of the armature is grounded.
6. Replace a grounded armature with a new one.

Tools: test lamp set

1. Connect one test lamp lead to a bare metal part of the generator frame.
2. Connect the other test lead to the coil terminal F+.
3. If the test lamp lights, a grounded circuit is indicated.
4. Remove the screws mounting one pole shoe to the frame.
5. Push the pole shoe and coil away from the frame.
6. If the ground is eliminated, the grounded coil is isolated.
7. Repeat until the grounded coil is located.
8. Repair the insulation at the point of damage.

Tools: continuity type test lamp set

1. Tag each lead wire and its connection point when disconnecting.
2. Connect one test lamp lead to the F+ coil terminals.
3. Connect the other test lamp lead to the F- coil lead.
4. If the lamp fails to light, an open circuit in the shunt winding is indicated.
5. Repeat the test between the S1 and F+ terminals.
6. If the lamp fails to light, an open circuit in the cranking winding is indicated.

Tools: sensitive ohmmeter

1. Use a sensitive ohmmeter to test the resistance of each coil winding.
2. If one coil reads more than 10% LESS than the average of the other three, it is short circuited.
3. On electric cranking models, do not confuse the cranking winding with the shunt winding.

Tools: test lamp set

1. Place one test prod on the commutator.
2. Place the second test prod on one of the slip rings.
3. If the test light glows, a short between the ac and dc windings is indicated.