Cummins/Onan 4.0CCK-3CR Generator Set

Tools: flat thickness gauge

1. Remove cover screws
2. Remove spark plugs
3. Turn flywheel clockwise about 1/4 turn after top center
4. Loosen screws A and turn cam B until gap is .020 in.
5. Retighten screws and recheck gap
6. Replace spark plugs and cover

Tools: idle adjustment tool

1. Run engine at no load
2. Turn idle needle in until engine slows considerably
3. Turn out until engine runs smoothly

Tools: main adjustment wrench

1. Connect full load
2. Turn main needle out about two turns
3. Turn in slowly until engine loses power
4. Turn out slowly until smooth at full power
5. Do not open more than 1/2 turn beyond maximum power

1. Loosen two cover retaining screws
2. Turn cover clockwise for less choking action
3. Turn counterclockwise for more choking action
4. Retighten cover screws

Tools: 1/16 in. diameter rod

1. Insert 1/16 in. rod through shaft hole into mounting flange notch
2. Loosen choke lever clamp screw
3. Adjust choke lever so plate is closed or not more than 5/16 in. open
4. Tighten screw and remove rod

⚠ Too much sensitivity will cause hunting

Tools: voltmeter or frequency meter

1. Check voltage and speed at no load and full load
2. Shift adjusting clip toward governor shaft to increase sensitivity
3. Shift clip toward outer end of governor arm to decrease sensitivity
4. Avoid hunting condition
5. Recheck speed adjustment

Tools: voltmeter or frequency meter

1. Run unit 15 minutes under light load
2. Disconnect or hold booster inactive
3. With no load, adjust governor spring tension to rated speed and voltage
4. Recheck speed adjustment

Tools: continuity test lamp

1. Connect continuity test lamp across breaker points
2. Turn crankshaft counterclockwise until points close
3. Slowly turn clockwise; lamp goes out as points break at 19° BTC

Tools: timing light

1. Connect timing light
2. Remove timing hole plug
3. Start engine and check mark aligns with 19° BTC
4. Loosen breaker box screws and move left to advance or right to retard
5. Start engine and verify
6. Tighten screws and replace timing plug

1. Adjust governor without booster
2. Connect booster external spring to bracket on governor link
3. At no load, slide bracket to position where external spring has no tension
4. Apply full load and check frequency rise
5. Lessen internal spring tension if rise is more than 2 hertz
6. Increase tension if frequency drops

Tools: suitable solvent

1. Lift off rubber breather cap
2. Pry or press valve from cap
3. Wash fabric flapper check valve in suitable solvent
4. Dry and install with perforated disc toward engine

1. One half hour at 1/2 load
2. One half hour at 3/4 load
3. Full load
4. Change crankcase oil after first 50 hours