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Cummins/Onan S Generator Set

The Cummins/Onan S is a 37.5 kW (41 kVA) Gasoline/LPG standby generator set powered by a Chrysler HB-225 engine. It is available at 12 V, 3-phase, 50 Hz and rated 35 A. It holds about 5.7 L (1.5 gal) of oil and 17 L (4.5 gal) of coolant. Starting uses 1 group-60 battery rated 360 CCA at 12 V. The set measures 1302×742×1845 mm (51.3×29.2×72.6 in) and weighs about 618.7 kg (1364 lb).

37 kW
Standby
3.68 L
Displacement
5.7 L
Oil capacity
3
Document types

How to read your Cummins/Onan serial & model number →

Specifications

FuelGasoline/LPG
Frequency50.0 Hz
Standby power37 kW
Standby kVA41
Prime power31 kW
Oil capacity5.7 L
AlternatorCummins/Onan YD15 (4-pole, Class Class B insulation)
Voltage options12 V
Phase3-phase
Rated current35 A
Battery group60
Battery cranking360 CCA
Battery voltage12 V
Battery quantity1
Coolant capacity17 L
Dimensions (L×W×H)1302×742×1845 mm
Dry weight618 kg

Engine

Chrysler HB-225
Oil capacity5.7 L
Coolant capacity17.0 L
Displacement3.68 L
AspirationGas/Gasoline/LPG
Rated speed1800 rpm

Maintenance & consumables

for the Chrysler HB-225
ItemSpecCapacityPart #Interval
Air filterAir Filter42222 PartsGeek FridayParts $104.15
Fuel filterFuel Filter1879579 PartsGeek
Oil filterEngine Oil FilterL324 PartsGeek
BeltDrive Belt— find
CoolantCoolant17.0 litres—
OilEngine Oil5.7 litres—

Common questions

What is the power rating of the Cummins/Onan S?

The Cummins/Onan S is rated 37 kW standby (41.0 kVA).

What engine does the Cummins/Onan S use?

The Cummins/Onan S is powered by the Chrysler HB-225 engine.

What fuel does the Cummins/Onan S use?

The Cummins/Onan S runs on Gasoline/LPG.

What is the oil capacity of the Cummins/Onan S?

The Chrysler HB-225 engine in the Cummins/Onan S has an oil capacity of 5.7 liters.

What alternator does the Cummins/Onan S use?

The Cummins/Onan S uses a Cummins/Onan YD15 alternator. It has 4 poles. Insulation class Class B.

What oil filter does the Cummins/Onan S use?

The Cummins/Onan S uses oil filter part number L324.

What fuel filter does the Cummins/Onan S use?

The Cummins/Onan S uses fuel filter part number 1879579.

What air filter does the Cummins/Onan S use?

The Cummins/Onan S uses air filter part number 42222.

Troubleshooting

13

Symptoms & remedies

SymptomRemedy
NO AC OUTPUT VOLTAGE AT RATED RPMIs control panel field breaker CB21 on? No - Replace defective and check continuity with ohmmeter. Is breaker open? Push to reset breaker. Does generator AC output voltage build up? If voltage is unstable, high or low, or causes breaker to trip, see Flow Charts B, C, D or E.
AC OUTPUT VOLTAGE BUILD UPFlash exciter field per TEST C. Does generator output voltage build up? Yes - across WE1 terminals 4 and 5 5 VDC or more? Yes - Check diodes CR1 through CR6 on rotor per TEST F. Replace if bad. Check exciter field wiring for shorts per TEST L Replace
NO AC OUTPUT VOLTAGE AT RATED ENGINE RPMReplace defective field breaker.
NO BUILD UP OF AC OUTPUT VOLTAGEIs reference voltage across TB21-1 & 2 20 VAC or more?
Engine stops cranking and fault lamp lights after cranking approximately 75 seconds. Overcrank diagnostic LED lit.Check fuel supply. See engine service manual for troubleshooting fuel and ignition systems.
Fault lamp lights immediately after engine starts. None of the diagnostic LED's illuminated.Check for overspeed condition as the engine starts.
Fault lamp lights and engine shutsdown after running for a period.Check for lighted check diagnostic LED'S. Check oil level, engine will shutdown if sensor is closed. Check Chrysler manual for troubleshooting oil system.
Fault lamp lights, none of the diagnostic LED's illuminated.Check Chrysler manual for troubleshooting oil system and cooling system.
Overcrank fault lamp lights and engine stops cranking after approximately 75-seconds.. See engine service manual for troubleshooting fuel system, ignition system, etc.
Engine runs, shuts down, cranks for 75-seconds, cranking cycle stops, overcrank light ON.. Check fuel supply, check ignition.
Low oil pressure shutdown.. Check — a. Oil level. Replenish if necessary. b. Sensor. Faulty sensor will shut down engine. c. Refer to engine service manual for troubleshooting guide for oil system.
High engine temperature shutdown.. Check — a. Coolant level. Replenish if necessary. b. City water cooled sets. Check water flow, valves, etc. c. Check sensor; check thermostat. d. Radiator model, check fan belts, radiator for obstructions, etc.
Overspeed shutdown.. Check governor and throttle linkages. for freedom of movement.

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

Parts

100
Part #DescriptionQtySystem
502-0047Nipple, Pipe (1/4)1Nipple PartsGeek
502-0971Connector, Hose2Hose PartsGeek
503-0183Clamp, Hose1Hose PartsGeek
503-0311Radiator Hose Clamp 2-1/8" x 1/2"1Hose PartsGeek
503-0354Clamp, Hose4Hose PartsGeek
503-0465Clamp, Hose2Hose PartsGeek
526-0013Guard. Belt Screw. Cap - Hex Head (1/2-13 X 3/4“)1Belt PartsGeek
821-0018Thermostat (Includes Plugs)1Thermostat PartsGeek
101-0769Service part / kit PartsGeek
104-0091*Nut, Hex (7!16-14) Washer, Lock Spring1Service part / kit PartsGeek
104-1185Service part / kit PartsGeek
104-1600Service part / kit PartsGeek
130-0449Cap, Radiator1Service part / kit PartsGeek
130-1196Service part / kit PartsGeek
130-3129Service part / kit PartsGeek
130-3131Service part / kit PartsGeek
130-3136Service part / kit PartsGeek
130-3157Service part / kit PartsGeek
130-3158Service part / kit PartsGeek
140-0078Service part / kit PartsGeek
140-1204Service part / kit PartsGeek FridayParts $209.00
140-1775Service part / kit PartsGeek
140-1869Service part / kit PartsGeek
140-2184Service part / kit PartsGeek
140-2189Service part / kit PartsGeek
145-0120Service part / kit PartsGeek
148-0737Regulator1Service part / kit PartsGeek
148-0775Service part / kit PartsGeek
148-0800Service part / kit PartsGeek
149-06381Service part / kit PartsGeek
149-0736Service part / kit PartsGeek
150-0638Service part / kit PartsGeek
150-2211Service part / kit PartsGeek
150-2212Service part / kit PartsGeek
151-0440Service part / kit PartsGeek
154-0133Service part / kit PartsGeek
160-1326Service part / kit PartsGeek
191-1833Service part / kit PartsGeek
191-1839Service part / kit PartsGeek
307-0268Valve, Solenoid1Service part / kit PartsGeek
332-1281149-2232 299202 31 332-2634 32 504-0028 33 98-4798 34 98-4732 3530Service part / kit PartsGeek
332-1292Bracket and Terminal Assembly1Service part / kit PartsGeek
402-02824 ftSnubber, Shock Mounting - Begin Spec K 341Service part / kit PartsGeek
402-0283Service part / kit PartsGeek
402-0288Service part / kit PartsGeek
402-0290Bushing (Front)3Service part / kit PartsGeek
402-0327Service part / kit PartsGeek
403-2614Service part / kit PartsGeek
403-2670Service part / kit PartsGeek
502-0054Elbow, Street - 90 DEG. (3/4NPT)1Service part / kit PartsGeek
502-0582Service part / kit PartsGeek
502-0587Service part / kit PartsGeek
503-0398Service part / kit PartsGeek
503-0429Screw, Self-locking (3/8-16 x 3/4“)1Service part / kit PartsGeek
503-0871Service part / kit PartsGeek
503-1068Service part / kit PartsGeek
503-1560Service part / kit PartsGeek
503-1561Service part / kit PartsGeek
503-1562Service part / kit PartsGeek
503-1564Service part / kit PartsGeek
504-0028Valve, Radiator Drain1Service part / kit PartsGeek
505-0017Bushing, Pipe – Reducer (3/8" to 1/4")2Service part / kit PartsGeek
505-0021Bushing, Pipe - Reducer (3/4º to 1/2º)1Service part / kit PartsGeek
505-0060Tube, Radiator - Upper1Service part / kit PartsGeek
505-0085Service part / kit PartsGeek
505-0099Nipple, Pipe (1/4 x .88)1Service part / kit PartsGeek
505-0106Service part / kit PartsGeek
505-0132Elbow, Exhaust (3/4" x 90")1Service part / kit PartsGeek
505-0135Nipple, Pipe - Half (3/8” NPT x 1-1/2” LG)2Service part / kit PartsGeek
511-0066Service part / kit PartsGeek
517-0259Service part / kit PartsGeek
520-0311Service part / kit PartsGeek
520-0969Service part / kit PartsGeek
526-00144 ttWasher (29/64" I.D. x 1-1/2" O.D. x 1/8") Only with Cone Shaped Cushions2Service part / kit PartsGeek
526-0026Screw, Cap - Hex Head (3/8-16 x 1-1/2")2Service part / kit PartsGeek
526-01954 tt29/64" I.D. x 3-1/4" O.D. x 1/8"1Service part / kit PartsGeek
526-0198As Req.tt5/8" I.D. x 1-1/2" O.D. x 1/16" 362Service part / kit PartsGeek
800-00345/16-18 X 2-1/4”1Service part / kit PartsGeek
800-00381 Brace Mounting (5/16-18 x 3-1/4") 52Service part / kit PartsGeek
800-0047Screw-HHC(3/8-16x5/8)1Service part / kit PartsGeek
800-0048Screw, Cap - Hex Head (3/8-16 x 3/4”)1Service part / kit PartsGeek
800-0050800 Amp (3/8-16 x 1)4Service part / kit PartsGeek
800-0051Screw-H}iC(3/8-16xl 1/4)1Service part / kit PartsGeek
800-0053Spring, Oil By-Pass3Service part / kit PartsGeek
800-0074Service part / kit PartsGeek
800-008210 WASHER, LOCKService part / kit PartsGeek
800-2088Service part / kit PartsGeek
805-0027Service part / kit PartsGeek
809-00367Service part / kit PartsGeek
814-0198Service part / kit PartsGeek
821-000512Service part / kit PartsGeek
821-002825Service part / kit PartsGeek
850-0045Washer, Lock - Spring (1/4" )2Service part / kit PartsGeek
850-0050Washer, Lock - Spring (3/8”)1Service part / kit PartsGeek
850-0055Washer, Lock - Spring (7/16")1Service part / kit PartsGeek
850-20106 Residential and Critical (M10)1Service part / kit PartsGeek
862-0003*Nut, Hex (3/8")1Service part / kit PartsGeek
862-00044 ttNut, Hex - Set Mounting - Key 2 HARDWARE SET, SET MOUNTING1Service part / kit PartsGeek
870-0217Service part / kit PartsGeek
946-0223Service 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

RatingLoadL/hgal/h
Prime100%4.416.7
Standby100%4.416.7

Available documents

Owner's manual — 946-0120 Onan SK series (spec A) Genset Operator's manual (08-1981) (Cummins/Onan)Parts manual — 946-0222 Onan SKB (spec A-B) Genset Parts manual (03-1992) (Cummins/Onan)Parts manual — 946-0223 Onan SK (spec A) Genset Parts manual (08-1987) (Cummins/Onan)Service manual — 900-0184 Onan YD Generators & Controls Service manual (11-1983)L (Cummins/Onan)