Specifications
| Fuel | gasoline |
|---|---|
| Frequency | 60.0 Hz |
| Standby power | 4 kW |
| Prime power | 4000 kW |
| Controller | Microprocessor Regulated |
| Oil capacity | 1.5 L |
| Voltage options | 120 V, 230 V |
| Phase | 1 |
| Rated current | 33.3 A |
| Battery cranking | 450 CCA |
| Battery voltage | 12 V |
| Dry weight | 79 kg |
| Tank runtime | [0.7, 1.0, 1.5] hr |
Filters & service parts
model family| Item | Spec | Capacity | Part # | Interval | |
|---|---|---|---|---|---|
| Air filter | — | 30 hr | find | ||
| Fuel filter | — | 450 hr | find | ||
| Oil filter | — | 150 hr | find | ||
| Belt | — | 250 hr | find | ||
| Coolant | — | 250 hr | |||
| Oil | Change the oil if the viscosity indicated is not appropriate for the temperatures expected. | 1.6 l | 15W40 | 20 hr | eBay $35.16 PartsGeek |
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 Cummins/Onan 4KY?
The Cummins/Onan 4KY is rated 4 kW standby.
What engine does the Cummins/Onan 4KY use?
The Cummins/Onan 4KY is powered by the Cummins/Onan KYD engine.
What fuel does the Cummins/Onan 4KY use?
The Cummins/Onan 4KY runs on gasoline.
What is the oil capacity of the Cummins/Onan 4KY?
The Cummins/Onan KYD engine in the Cummins/Onan 4KY has an oil capacity of 1.5 liters.
Troubleshooting
42Fault codes
| Code | Meaning | Remedy |
|---|---|---|
| STATUS INDICATOR LIGHT DEAD | Faulty connections, no battery voltage | 1. Try the genset Start Switch if the remote Start Switch does not work, and vice versa. 2. Clean and tighten the positive (+) and negative (−) battery cable connections at the battery, vehicle frame and genset. 3. Recharge or replace the battery. Refer to the battery manufacturer’s recommendations. |
| NO. 38 | OVERCURRENT FAULT—CODE NO. 38 (Low power factor loads) | 1. Reduce the number of appliances running at the same time, especially those with high motor starting loads such as air conditioners. 2. Have air conditioners and other appliances checked for proper operation. (A locked compressor rotor can cause very low power factor.) |
| NO. 41 | GENERATOR ROTOR FAULT—CODE NO. 41 (Controller unable to sense field or output voltage) | See an authorized Onan dealer. |
| NO. 42 | PROCESSOR FAULT—CODE NO. 42 (Microprocessor ROM error during self-test) | See an authorized Onan dealer. |
| NO. 43 | PROCESSOR FAULT—CODE NO. 43 (Microprocessor RAM error during self-test) | See an authorized Onan dealer. |
| NO. 45 | SPEED SENSE FAULT—CODE NO. 45 (Controller unable to sense quadrature frequency) | See an authorized Onan dealer. |
| NO. 47 | IGNITION FAULT—CODE NO. 47 (Controller unable to sense ignition) | See an authorized Onan dealer. |
| NO. 48 | GENERATOR FIELD SENSE FAULT—CODE NO. 48 (Controller unable to sense field voltage) | See an authorized Onan dealer. |
| 3 | Service Check Fault | |
| 4 | Overcrank | |
| 12 | Overvoltage | |
| 13 | Undervoltage | |
| 14 | Overfrequency | |
| 15 | Underfrequency | |
| 27 | Voltage Sense Lost | |
| 29 | High Battery Voltage | |
| 32 | Low Cranking Speed Sense | |
| 33 | Fault Code 33 | |
| 35 | Control Card Failure | |
| 36 | Genset Stopped Without Fault Condition | |
| 38 | Field Overload (Overvoltage) | |
| 41 | Generator Rotor Fault | |
| 42 | Processor Fault | |
| 45 | Speed Sense Fault | |
| 48 | Field Sense Fault | |
| 51 | Processor Failure | |
| CODE NO. 38 | OVERCURRENT FAULT—Low power factor loads | 1. Reduce the number of appliances running at the same time, especially those with high motor starting loads such as air conditioners. 2. Have air conditioners and other appliances checked for proper operation. (A locked compressor rotor can cause very low power factor.) |
| CODE NO. 41 | GENERATOR ROTOR FAULT—Controller unable to sense field or output voltage | See an authorized Onan dealer. |
| CODE NO. 42 | PROCESSOR FAULT—Microprocessor ROM error during self-test | See an authorized Onan dealer. |
| CODE NO. 43 | PROCESSOR FAULT—Microprocessor RAM error during self-test | See an authorized Onan dealer. |
| CODE NO. 45 | SPEED SENSE FAULT—Controller unable to sense quadrature frequency | See an authorized Onan dealer. |
| CODE NO. 47 | IGNITION FAULT—Controller unable to sense ignition | See an authorized Onan dealer. |
| CODE NO. 48 | GENERATOR FIELD SENSE FAULT—Controller unable to sense field voltage | See an authorized Onan dealer. |
Symptoms & remedies
| Symptom | Cause | Remedy |
|---|---|---|
| Generator output connections must be made by a qualified electrician | Make generator output connections only by a qualified electrician in accordance with applicable codes. | |
| The genset must not be connected to the public utility or any other source of electrical power. | Do not connect the genset to the public utility or any other source of electrical power. Use an approved switching device to prevent interconnections. | |
| Generator sets use substances that can cause health risks | Use appropriate personal protective equipment when exposed to fuel, oil, coolant, wet batteries, grease, cleaning agents, or other substances. Use proper containers for transport, storage, and disposal of waste substances. Follow local regulations. | |
| STARTING BATTERIES RUN DOWN | (Marginal batteries, connections, or charging system or, parasitic loads) | 1. Clean and tighten the positive (+) and negative (−) battery cable connections at the battery, vehicle frame and genset. 2. Recharge or replace the battery. Refer to the battery manufacturer’s recommendations. 3. Have a battery charging system installed or serviced in the vehicle. |
| STARTER ENGAGES-DISENGAGES | (Cranking voltage dips below 6 volts—low battery charge, poor connections, long cables) | 1. Have the vehicle propulsion engine running while trying to start the genset—the battery charging alternator may be able to maintain starting voltage high enough to get the genset started. 2. Clean and tighten the positive (+) and negative (−) battery cable connections at the battery, vehicle frame and genset. 3. Recharge or replace the battery. Refer to the battery manufacturer’s recommendations. 4. Increase battery cable size or run parallel cables. |
| STATUS INDICATOR LIGHT GOES OUT WHILE CRANKING—NO START | (Internal short circuit caused automatic-reset circuit protective device to trip) | Try starting again. See an authorized Onan dealer if the status indicator light flashes and then goes out again without the engine starting. |
| NO POWER—GENSET RUNNING, STATUS LIGHT ON | (Line circuit breaker OFF, or tripped due to short circuit or overload) | 1. Turn on or reset the line circuit breaker on the genset (Page 2-3). 2. Turn on or reset the line circuit breakers on the main distribution panel in the vehicle. |
| Cranking voltage dips below 6 volts | Low battery charge, poor connections, long cables | Have the vehicle propulsion engine running while trying to start the genset—the battery charging alternator may be able to maintain starting voltage high enough to get the genset started. Clean and tighten the positive (+) and negative (−) battery cable connections at the battery, vehicle frame and genset. Recharge or replace the battery. Refer to the battery manufacturer’s recommendations. Increase battery cable size or run parallel cables. |
| STATUS INDICATOR LIGHT DEAD (Faulty connections, no battery voltage) | 1. Try the genset Start Switch if the remote Start Switch does not work, and vice versa. 2. Clean and tighten the positive (+) and negative (−) battery cable connections at the battery, vehicle frame and genset. 3. Recharge or replace the battery. Refer to the battery manufacturer’s recommendations. |
Fault codes and symptom→remedy steps extracted from this model’s service/owner documentation; verify against the official manual before servicing.
Parts
8| Part # | Description | Qty | System | |
|---|---|---|---|---|
| 0611-1268-2 | RECONNECTION DIAGRAMS | Output connections | PartsGeek | |
| 0500-3297-1 | STANDARD RIGID UNDERFLOOR MOUNTING KIT (403-3608) | Service part / kit | PartsGeek | |
| 0500-3297-2 | UNDERFLOOR BASE KIT (403-3630) | Service part / kit | PartsGeek | |
| 0500-3297-3 | SOFT UNDERFLOOR MOUNTING KIT (403-3670) | Service part / kit | PartsGeek | |
| 403-3608 | STANDARD RIGID UNDERFLOOR MOUNTING KIT | Service part / kit | PartsGeek | |
| 403-3630 | UNDERFLOOR BASE KIT | Service part / kit | PartsGeek | |
| 403-3670 | SOFT UNDERFLOOR MOUNTING KIT | Service part / kit | PartsGeek | |
| 539-4814 | floor template for floor opening cutouts | Service part / kit | PartsGeek |
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
| Rating | Load | L/h | gal/h |
|---|---|---|---|
| Full load | 0.71 | 2.7 | |
| Half load | 0.48 | 1.8 | |
| No load | 0.29 | 1.1 | |
| Prime | |||
| Standby | |||
| Standby | 1.1 | 0.29 | |
| Standby | 50% | 1.8 | 0.48 |
| Standby | 100% | 2.7 | 0.71 |
Available documents
Installation manual — 981-0621 Onan KY Installation Manual (5-2000)) (Cummins/Onan)Installation manual — 981-0636 Onan KYD Mobile Genset Operator's manual w-981-1054 Supplement (12-2005) (Cummins/Onan)Service manual — 0981-0621 (Cummins/Onan)Service manual — 981-0169B Onan KYD Mobile Genset Operator's manual (11-2004)Service manual — 981-0530C Onan KY (spec J) KYD (spec A) RV Genset Service Manual (01-2006) (Cummins/Onan)Service manual — onan3600manual (Cummins/Onan)