Specifications
| Fuel | Gasoline |
|---|---|
| Frequency | 60.0 Hz |
| Standby power | 4 kW |
| Controller | Decision-Maker |
| Oil capacity | 1.89 L |
| Voltage options | 120 V |
| Phase | 1 |
| Rated current | 37.5 A |
| Battery voltage | 12 V |
| Battery quantity | 1 |
| Dimensions (L×W×H) | 604×462×484 mm |
| Dry weight | 107 kg |
Filters & service parts
model family| Item | Spec | Capacity | Part # | Interval | |
|---|---|---|---|---|---|
| Air filter | Clean element regularly; replace every 200 hours | — | 200 hr | find | |
| Oil filter | 5.5CM/7CM only (full-flow oil filter); adds 0.5 qt oil capacity when replaced | — | find | ||
| Oil | API service class SF; straight SAE 30 preferred (see viscosity chart) | — |
Compiled from this model's family documentation — may include parts for closely-related variants. Confirm the exact part for your serial number.
Common questions
What is the power rating of the Kohler 4.5CM21?
The Kohler 4.5CM21 is rated 4 kW standby.
What engine does the Kohler 4.5CM21 use?
The Kohler 4.5CM21 is powered by the Kohler K341QS engine.
What fuel does the Kohler 4.5CM21 use?
The Kohler 4.5CM21 runs on Gasoline.
What is the oil capacity of the Kohler 4.5CM21?
The Kohler K341QS engine in the Kohler 4.5CM21 has an oil capacity of 1.89 liters.
Troubleshooting
18Symptoms & remedies
| Symptom | Cause | Remedy |
|---|---|---|
| Hard Starting or Loss of Power | . Faulty Ignition. .a. Loose or grounded high tension or breaker point leads. .b. Improper breaker point gap and timing. .c. Defective breaker points. .d. Faulty spark plug or improper gap. .e. Faulty condenser or coil. .gasoline not getting to carburetor. a. Dirt or gum in fuel fine. b. Fuel pump faulty. c. Dirt in carburetor. d. Carburetor improperly adjusted. e. Choke faulty or improperly adjusted. | |
| Overheating | . Insufficient available cool air. . Dirty air intake screen, shroud or cooling fins. . Improper fuel. . Fuel mixture too lean. . Improper ignition timing. . Engine overloaded. . Tight tappet clearance. . Insufficient hot-air discharge opening. | |
| Backfiring | . Fuel mixture too lean. . Improper timing. . Valve ‘Sticking’. | |
| Occasional 'Skip' at High Speed | 1. Spark plug misfire or failure. | |
| No AC output, green lamp off. | Fuse in controller blown (5-3). | Refer to Kohler Service Manual for Repair. |
| Engine starts, then stops when start switch is released. | 10 amp fuse blown (5-3). If blows after replacement check for defective wiring, generator and generator voltage regulator. | |
| Engine runs, AC voltage is present but green lamp does not come on. | 1 amp fuse blown (5-3). | |
| Engine will not crank. | . Defective switch circuit board (5-4). . Loose pin in electrical connector. . Open in foil pattern of Main Circuit Board. | |
| Engine cranks but will not start. | . Defective main circuit board (5-4). . Foil burnt (5-5). . Defective choke. . In line fuse to ignition coil blown. | |
| Engine shuts down. | . 10 amp in-line fuse blown (5-3). . Radiated electrical noise from ignition circuit affecting logic circuitry in the controller. | |
| No AC output, green lamp ‘on’. | Circuit protector left in OFF position. Reset to ON position. If the breaker trips after starting, reduce the load on the generator set. | |
| Short circuit. | Check all wiring and voltage regulator. | |
| Low output or excessive drop in voltage, green lamp ‘ON’. | . Set overloaded. Reduce the foad. . Defective voltage regulator. Replace. | |
| Engine wil! not crank properly. | Check for loose wiring connections. | |
| Low AC voltage. (Below 110V). | . Worn brushes (6-5). . Defective voltage regulator (6-7); replace. NOTE: Before installing use thermal compound (#287945) and apply thin coat on base of regulator. | |
| High AC voltage. | . Defective voltage regulator (6-7); replace. NOTE: Before installing, use thermal compound (#287945) and apply thin coat on base of regulator). | |
| Engine starts, then stops when start switch is released (no red or green light). | Check the 110 Volt AC output at available outlet while the start button is being held on. If AC output is present, replace AC interlock board (6-10). If no 110 Volt AC output is present — a. Check for open or short circuit. b. Check brushes (6-5) for cracks or broken leads and make sure they are making proper contact on the slip rings. c. Check rotor (6-9) and stator (6-8) resistance. d. Check voltage regulator (6-7). If defective, replace voitage regulator. NOTE: Before installing apply thermal compound (thin coat) on base of regulator. e. Check stator (6-8) for grounded, open or shorted windings. | |
| Engine runs, AC voltage is present, engine stops running after a short time. | Faulty exciter voltage regulator (6-7). |
Fault codes and symptom→remedy steps extracted from this model’s service/owner documentation; verify against the official manual before servicing.
Parts
3model family| Part # | Description | Qty | System | |
|---|---|---|---|---|
| 287945 | Thermal compound, thin coat applied to base of exciter voltage regulator before installation | Fluid | PartsGeek | |
| A-269150 | Generator interlock circuit board (early version) | 1 | Sensor | PartsGeek |
| B-269150 | Generator interlock circuit board (revised version) | 1 | Sensor | PartsGeek |
Compiled from this model's family documentation — may include parts for closely-related variants. Confirm the exact part for your serial number. See the full parts catalog to search and cross-reference.
Available documents
Service manual — TP5014 Kohler Gen Service 3.5CM21 4.5CM21 7CM21 (11-1987) (Kohler)