Kohler 12C Generator Set

Tools: belt tension gauge

1. Position belt tension tool on drive belt.
2. Check tension per tool manufacturer instructions.
3. Loosen alternator and/or governor mounting and adjusting bolts.
4. Move component away from engine until correct tension obtained.
5. Retighten mounting bolts.

⚠ Do not tamper with -2.5 Hz/Freq terminals during governor adjustment.

Tools: jumper wires, voltmeter

1. Verify swivel on actuator arm fully threaded and secured.
2. Adjust throttle rod to approx. 3-7/8 in. (98 mm) between ball joints.
3. For 50 Hz install jumper across 50/60 Hz terminals; for 60 Hz no jumper.
4. Install jumper across Gain Change terminals; set gain pot to 3.
5. Start set, apply full load; adjust gain until actuator stable.
6. Check battery voltage at governor board + and - terminals: at least 11 V DC.
7. Check AC voltage at Gen Volt terminal: at least 90 V AC.
8. If needed, lengthen actuator rod linkage one turn.

⚠ Do not rotate crankshaft counterclockwise.

Tools: 10 mm socket wrench, feeler gauge, ratchet wrench

1. Remove rocker arm cover and oil breather cap.
2. Rotate crankshaft clockwise until No.1 at TDC compression.
3. Insert feeler gauge between rocker arm and exhaust valve; adjust.
4. Repeat for intake valve.
5. Rotate crankshaft 180 degrees clockwise; set No.2.
6. Rotate 180 degrees; set No.4.
7. Rotate 180 degrees; set No.3.
8. Install rocker arm cover; torque screws 3-4 ft lbs (4-5 Nm).

⚠ Heat sink contains high voltage.

Tools: voltmeter, frequency meter, jumper wire

1. With set off, turn remote rheostat to mid-point.
2. Turn voltage, Volts/Hz, and stability pots fully counterclockwise.
3. Start set; rotate voltage pot to desired output voltage.
4. Rotate stability pot clockwise until minimum light flicker.
5. Install jumper on governor -2.5Hz/Freq terminals.
6. Rotate Volts/Hz pot clockwise until voltage begins to drop.
7. Remove jumper from governor circuit board.
8. Readjust voltage and stability pots if necessary.

⚠ Heat sink contains high voltage.

Tools: voltmeter, frequency meter, jumper wire

1. With set off, turn remote rheostat and stability pots to mid-point.
2. Turn voltage and Volts/Hz pots fully counterclockwise.
3. Start set; rotate voltage pot to desired output voltage.
4. Rotate stability pot clockwise until minimum light flicker.
5. Install jumper on governor -2.5Hz/Freq terminals.
6. Rotate Volts/Hz pot clockwise until voltage begins to drop.
7. Remove jumper from governor circuit board.
8. Readjust stability and voltage pots if necessary.

⚠ Hazardous voltage.

Tools: ammeter, 12 V automotive battery

1. Disconnect all leads from voltage regulator.
2. Connect ammeter and 12 V battery to positive and negative brush leads.
3. Record ammeter reading; approx. battery voltage divided by rotor resistance.
4. Start engine and check ammeter remains stable.
5. Check AC output across stator leads.
6. If rotor and stator test good, voltage regulator is likely defective.

⚠ Hazardous voltage.

Tools: ammeter, 12 V battery

1. Disconnect all leads from voltage regulator.
2. Remove exciter field F1 and F2 leads from TB2.
3. Connect ammeter in series with F1 and 12 V battery.
4. Record ammeter reading.
5. Start engine and check ammeter remains stable.
6. Check AC output across stator leads.
7. If rotor and stator test good, voltage regulator is likely defective.

⚠ Do not operate with air cleaner removed.

1. Remove air cleaner element.
2. Clean all dust and foreign matter from housing.
3. Install new air cleaner element.
4. Replace element every 400 hours or 6 months.
5. Replace more often in dusty conditions.

⚠ Allow engine to cool before opening pressure cap.

1. Close drain plug and petcock.
2. Fill radiator with recommended coolant mixture.
3. Operate engine until thermostat opens and upper hose is hot.
4. Stop engine and add coolant to 3/4 to 1-1/2 in. (19-38 mm) below filler neck.

⚠ Hot oil can cause burns.

Tools: container, wrench

1. Place container beneath oil drain plug.
2. Loosen drain plug; allow oil to drain completely.
3. Remove oil filter.
4. Replace drain plug and tighten securely.
5. Install new oil filter.
6. Add proper oil to crankcase until dipstick reads safe.

⚠ Do not overtighten spark plugs.

Tools: feeler gauge, plug wrench, compressed air

1. Clean area around spark plug with compressed air.
2. Remove spark plug cap and spark plug.
3. Inspect plug; replace if insulation cracked or damaged.
4. Measure gap with feeler gauge.
5. Adjust gap to 0.039 in. (1.0 mm).
6. Thread plug by hand until snug.
7. Tighten to 11-15 ft lbs (15-20 Nm).
8. Replace spark plug cap.

⚠ Accidental starting hazard.

Tools: hoist, screwdriver, wrench

1. Disconnect battery, negative lead first.
2. Remove end bracket louvered panel on CZ.
3. Remove junction box side panels and controller cover.
4. Disconnect P5 connector, brush leads, stator leads.
5. Remove support bracket.
6. Remove voltage regulator on CC.
7. Raise generator and support.
8. Remove overbolts and end bracket.