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Kohler 12C Generator Set

The Kohler 12C is a 12 kW (120 kVA) standby generator set. It is available at 240 V and 120/240 V, 3-phase and 60 Hz. It holds about 7.9 L (2.1 gal) of oil. The set measures 1094.2×558.8×675.3 mm (43.1×22.0×26.6 in).

12 kW
Standby
7.9 L
Oil capacity
1
Document types

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Specifications

Frequency60.0 Hz
Standby power12 kW
Prime power12 kW
Oil capacity7.9 L
Voltage options240 V, 120/240 V
Phase3
Dimensions (L×W×H)1094×558×675 mm

Maintenance & consumables

ItemSpecCapacityPart #Interval
Oil filter279218 Amazon $42.83 eBay

Common questions

What size generator is the Kohler 12C?

The Kohler 12C is rated 12 kW standby.

What oil filter does the Kohler 12C use?

The Kohler 12C uses oil filter part number 279218.

Troubleshooting

16

Fault codes

CodeMeaningRemedy
LOPLow Oil Pressure (LOP) Shutdown
HETHigh Engine Temperature
SDROverspeed ShutdownDeenergize engine components

Symptoms & remedies

SymptomCauseRemedy
Unit will not crankWeak or dead battery, Reversed or poor battery connections, Defective starter solenoid, Defective starter, Defective start/stop switch (controller or remote), Fuse blown in controller, Open in wiring , terminal pin, foil etc. (P1/P2/P3 connector)Recharge or replace battery. Check connections., Test and/or replace solenoid See Section 8 and Section 12., Test function of switch. See Section 8 and Section 12., Replace fuse; if fuse blows again, check circuit and components. See Section 8., Check continuity. See Section 9 and Section 12.
StartCranks but will not start, Out of fuel, Air cleaner clogged, Defective fuel solenoid **, Defective ignition system (spark control or ignition coil), Faulty spark plugs or loose connections, Defective/misadjusted choke **, Defective fuel pump **, Clogged fuel filter **, Defective fuel regulator/valve (on LP/natural gas systems), Faulty ground (-) connectionReplenish fuel supply. Clean or replace. See Section 3., Test and/or replace solenoid See Engine Service Manual,”Starting System.”, Test and/or replace components. See engine service manual, |'Ignition System—Distributorless”, Replace (and regap) spark plugs See Section 3, Spark Plugs.”, Replace/readjust choke See Section 3. ”Choke Adjustment” and Section 8., Verify operation with 12 Volts DC applied. Check fuel pressure of 2-3.5 psi (14-24 kPa). See Section 8 for additional info., Replace fuel filter. See Section 3. ”Fuel Filter Service.”, Check regulator/valve operation. See Section 3, 'Straight Gas Fuel System” and Section 8., Clean and retighten
Engine starts but stops after start switch is releasedDefective controller main circuit board, Engine defective (stuck valves poor compressionTest circuit board operation as described in Section 8., Repair engine. See engine service manual.
No generator outputSeparately excite generator. Check AC voltage and stator continuity. See Section 7 and Section 8.
Low oil pressure (LOP) shutdownCheck engine oil level, oil pressure and oil pump. Operating oil pressure is approximately 21.7 psi (150 kPa). LOP switch contacts close at oil pressure below 15 psi (103 kPa). See Section 3 (for location), Section 8, and engine service manual.
High engine temperature (HET) shutdownAttempt start-up. If unit shuts down, remove lead from LOP switch. A successful restart attempt indicates a faulty LOP shutdown switch. LOP contacts close at approximately
Stops suddenlyOut of fuel, Air cleaner clogged, Fuse blown in controller, Faulty spark plug(s), High engine temperature (HET) shutdown, Low oil pressure (LOP) shutdown, Overspeed shutdown, Defective fuel valve/fuel regulator (on LP/natural gas systems only), Defective fuel pump **, Vapor lock **, Clogged fuel filter **, Defective fuel solenoid **, Defective ignition system (spark control or ignition coil)Replenish Replace element. See Section 3. Replace fuse. See Section 2. Replace fand regap) plug(s). See Section 3 Inspect cooling : system (low coolant level, loose belt, radiator obstructions, etc.). See Section 3. Check engine oil level, oil pressure and oil pump. Operating oil pressure is approximately 21.7 psi (150 kP. At LOP switch contacts close at oil pressure below 15 psi (103 kPa). See Section 3 (for location), Section 8, and engine service manual. Check electronic governor and voltage regulator. See Section 8. Check regulator/valve operation. See Section 3 and Section 8. Check fuel pump operation. See Verify operation with 12 Volts DC applied. Check fuel pressure of 2-3.5 psi (14-24 kPa). See Section 3 and Section 8 for additional information. Check fuel line routing Replace filter. See Section 3. Test and/or replace solenoid. See Section 8. Test and/or replace components. See engine service manual, 'Ignition System-Distributorless'
Operates erraticallyAir cleaner clogged, Dirty fuel filter, Stale or bad fuel, Faulty spark plugs, Carburetor adjustment incorrect, Carburetor choke improperly adjusted, Governor adjustment incorrect, Defective fuel pump **, Carbon build—up in engine, Engine valves not seating properlyReplace element. See Section 3. Replace filter. See Section 3. Replace fuel Replace (and regap) plugs. See Section 3. Readjust carburetor. See Section 3. Readjust choke. See Section 3. Adjust electronic governor. See Section 8. Verify operation with 12 Volts DC applied. Check fuel pressure of 2-3.5 psi (14-24 kPa). See Section 8 for additional information. Clean cylinder head. See engine service manual. Inspect valves and valve seats. See engine service manual.
Lacks powerAir cleaner clogged, Generator overloaded, Bad or stale fuel, Faulty spark plug(s), Carburetor adjustment incorrect, Engine not running at rated rpm, Governor defective or misadjusted, Improper cooling, Choke misadjusted **, Fuel line restriction, Dirty fuel filter **, Defective ignition system (spark control or ignition module), Carbon build-up in engineReplace element. See Section 3. Reduce load. See Section 2, 'Line Circuit Breaker.' Replace fuel Replace (and regap) plug(s). See Section 3. Readjust carburetor as described in Section 3. Adjust governor. See Section 8. Test/readjust governor. See Section 8. Inspect cooling system (low coolant level, loose belt, radiator obstructions, etc.). See Section 3. Readjust choke. See Section 3. Inspect fuel lines Replace fuel filter. See Section 3. Test and/or replace. See engine service manual. Clean cylinder head. See engine service manual.
OverheatsImproper cooling, Air cleaner clogged, Carburetor adjustment incorrectInspect cooling system (low coolant level, loose belt, radiator obstructions, etc.). See Section 3. Replace element. See Section 3. Readjust carburetor. See Section 3.
Overspeed ShutdownWhen engine speed exceeds 70 Hz (2100 rpm) on 50/60 Hz sets, SDR relay normally—-open contacts close to energize K4 relay (LED 4 lights). K4 normally-closed contacts open to deenergize engine components. Unit shuts down.
No or low AC outputGenerator field (rotor) may be excited (magnetized) using an outside power source (12 Volt automotive battery). In the separate excitation test, you will be duplicating the role of the voltage regulator in providing excitation current to the rotor. By separately exciting the generator to determine the presence of a faulty voltage regulator, it is possible to determine if a running fault exists in the rotor and/or stator.
No or low AC output on CC/4-lead generatorsGenerator field (rotor) may be excited (magnetized) using an outside power source (12 Volt automotive battery). In the separate excitation test, you will be duplicating the role of the voltage regulator in providing excitation current to the rotor. By separately exciting the generator to determine the presence of a faulty voltage regulator, it is possible to determine if a running fault exists in the rotor and/or stator.

Fault codes and symptom→remedy steps extracted from this model’s service/owner documentation; verify against the official manual before servicing.

Parts

2
Part #DescriptionQtySystem
X-758-1Generator end bracket bearing, used with end bracket not stamped with the letter 'P'1Service part / kit buy
X-758-17Generator end bracket bearing, used with end bracket stamped with the letter 'P'Service part / kit buy

Service, wear & replacement parts referenced for this model and its engine — confirm the exact part for your serial number. See the full parts catalog to search and cross-reference.

Fuel consumption

RatingLoadL/hgal/h
Prime
Standby

Available documents

Service manual — 10-12 CC-CZ-CFC-CFZ Service Manual Kohler (Kohler)Service manual — TP5422 Kohler Gen Service 10CC 12CC 10CZ 12CZ (09-90) (Kohler)