Cummins/Onan AJ series Generator Set

Tools: voltmeter

1. Connect voltmeter across generator output.
2. With no electrical load, start plant and adjust speed adjusting nut to approximately 126 V maximum for 115 V plant.
3. Apply full rated load; voltage should be approximately 108 V minimum.
4. For 230 V plants, 252 V no load maximum and 216 V full load minimum.
5. If voltage spread too great, move end of speed spring closer to governor shaft.
6. If hunting, turn sensitivity stud outward slightly; readjust speed.

Tools: ammeter

1. Turn knurled speed adjusting nut to desired charging rate on ammeter.
2. If governor hunts, turn sensitivity adjusting stud outward.
3. Any sensitivity change requires compensating speed adjustment.
4. Maximum speed at full load approximately 2400 rpm.

1. Turn adjusting needles in gently to seats; do not force.
2. Back main needle out about 2-1/2 full turns.
3. Back idle needle out about 3/4 turn.
4. Start plant and warm up under full load.
5. Slowly turn main needle inward until plant loses speed or voltage drops.
6. Turn main needle outward until plant carries full load.
7. If hunting, turn main needle out for richer mixture, not more than 1/2 turn beyond maximum output.
8. Adjust idle needle warm, batteries connected, no AC load; turn inward until plant loses speed, then outward until smooth.
9. Adjust throttle idle stop screw to clear throttle shaft stop by 1/32 in at desired speed and no load.

Tools: 7/16 in wrench, 9/16 in wrench

1. Remove valve compartment cover and blower housing.
2. Crank engine by hand until intake valve opens and closes.
3. Continue turning flywheel slowly until flywheel mark aligns with TC mark on gear cover.
4. Check tappet clearance per Table of Clearances.
5. Use 7/16 in wrench for adjusting screw and 9/16 in wrench for tappet.

1. See that point gap is properly adjusted.
2. Install flywheel loosely with key in place.
3. Turn flywheel in rotation direction until mark aligns with proper degree mark on gear cover.
4. Points should just separate at this point.
5. If not, remove flywheel and loosen magneto backplate mounting screws slightly.
6. If points separate too soon, shift backplate clockwise; if too late, counterclockwise.
7. Retighten screws and recheck; ensure flywheel key is in place.

⚠ Failure to center starter properly will damage starter.

Tools: screwdriver, pliers

1. Remove existing rope sheave from engine flywheel; reuse flat washer and lock washer.
2. Secure cup using lock washer and flat washer between cup and cap screw.
3. Assemble mounting ring to starter with four screws in desired rope-pull position.
4. Place three U-shaped speed nuts on engine housing.
5. Place starter against blower housing; check centering pin engages cup-and-flywheel capscrew center hole.
6. Use three sheet metal screws to mount starter securely.
7. Check approximately 1/8 in clearance between cup and rotor face and minimum 3/32 in between capscrew and starter shaft.

⚠ Do not bring open flame or burning cigarette near batteries on charge.

Tools: hydrometer, filler bulb

1. Fully charge battery.
2. While on charge, siphon off electrolyte above plates in each cell.
3. Fill each cell with pure distilled water.
4. Recharge one hour at 4 to 6 ampere rate.
5. Test each cell with hydrometer; if specific gravity above 1.225, repeat steps 2, 3, and 4.
6. Continue until highest fully charged reading is not over 1.225.

1. Insert load plug into receptacle at side of generator.
2. Turn plug slightly right to lock.
3. Provide a ground on the plant if tools or appliances have a third wire for grounding.
4. Throw individual load switch ON.

⚠ Continuous overloading may damage generator windings.

1. Allow plant to warm up thoroughly before connecting heavy load.
2. Throw main line switch to ON; if no main line switch, throw individual load switch ON.
3. Apply portions of load in steps when possible.

1. See that carburetor is properly filled.
2. Adjust manual carburetor choke as necessary for temperature.
3. Wind starting rope on flywheel rope sheave clockwise to within a few inches of handle.
4. Crank once with a strong, fast pull the full length of rope.
5. If no start, change choke setting and repeat.
6. As plant warms up, gradually open choke to running position.

1. Before first start or after running out of fuel, work fuel pump primer lever or crank until carburetor fills, about 30 revolutions.
2. Push START-STOP toggle switch to START.
3. Carburetor is automatically choked.
4. If plant does not start after a few crankings of about 5 seconds each, check fuel and ignition systems.
5. Release start switch as soon as plant starts; ensure it returns to center.
6. Check each remote control switch in START and STOP positions.

1. Be sure carburetor is filled with gasoline.
2. Do not have a heavy electrical load connected.
3. Engage knot of starting rope in flywheel rope sheave notch.
4. Wind rope clockwise to within a few inches of handle.
5. Crank with a strong, fast pull the full length of rope; do not jerk.
6. Repeat as necessary; check fuel and ignition if no start.
7. Be sure starting batteries are connected.