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Kohler 25EFOZD Generator Set

The Kohler 25EFOZD is a 25 kW (25 kVA) diesel standby generator set. It is available at 230 V and 240 V, single-phase, 50 Hz and rated 108.7 A. The set measures 1295×635×810 mm (51.0×25.0×31.9 in) and weighs about 626 kg (1380 lb).

25 kW
Standby
4
Document types

How to read your Kohler serial & model number →

Typical fuel consumption for 25–30 kW Diesel generators →

Compare with other 25–30 kW Diesel generators →

Specifications

Fueldiesel
Frequency50.0 Hz
Standby power25 kW
Standby kVA25
Prime power25 kW
ControllerADC 2100
AlternatorFast-Response X
Voltage options230 V, 240 V
Phase1
Rated current108.7 A
Dimensions (L×W×H)1295×635×810 mm
Dry weight626 kg

Fault codes

2
CodeNameMeaningSeverityAction
CO-3Fault displayed if the CO parameter is set incorrectlyShutdown
CO-6Fault displayed if the CO parameter is set incorrectlyShutdown

Extracted from the manufacturer documentation linked to this model. Values are copied as printed; confirm against your unit's manual and serial number.

Procedures

3
Controller Configuration adjustment

⚠ Be sure to save the new settings immediately before exiting the configuration mode; changes are lost if the controller times out (about 1 minute).

  1. Hold the Select button and move the master switch to RUN to enter configuration mode.
  2. Press the down arrow key then the up arrow key 3 times to enter configuration mode (password).
  3. Set the voltage/frequency parameter Uu for the model.
  4. Set the unit configuration parameter Uc (marine, standby, mobile).
  5. Set the engine type parameter Ec.
  6. Press the up arrow at the Adnc display to enter advanced configuration mode.
  7. Set the engine data input type Ed.
  8. Set the battery voltage Bt (12 or 24 VDC).
  9. Set the communications parameter Cn.
  10. Enter save mode and save your settings before exiting.
Output Voltage and Frequency Adjustment adjustment

⚠ The generator set must be running during these adjustments.

⚠ The engine speed (frequency) adjustment menus are not accessible on models with mechanical governors.

Tools: multimeter

  1. Move the master switch to RUN; the engine starts and runtime hours display.
  2. Hold the Select button about 5 seconds until the program version number displays.
  3. Press the down arrow key then the up arrow key 3 times to enter adjustment mode.
  4. 1P: adjust voltage coarse in large increments (approximately 5-7 volts per step).
  5. 2P: adjust voltage fine in smaller increments (approximately 0.5-0.7 volts per step).
  6. Adjust voltage stability (gain) coarse and fine.
  7. 3P: set volts/Hz (00=low, 09=high).
  8. 4P: adjust engine governor speed coarse and fine.
  9. 5P: adjust engine governor stability (gain) coarse and fine.
  10. Enter SAVE mode and save settings before exiting the adjustment mode.
Controller Replacement installation

⚠ Disconnect the battery cables before working on the generator set; remove the negative lead first and reconnect it last.

Tools: multimeter, personal computer with Program Loader Software

  1. Record generator set information required for configuration: model, market, voltage, frequency, phases, battery voltage.
  2. Place the generator set master switch in the OFF position.
  3. Disconnect power to the battery charger, if equipped.
  4. Disconnect the engine starting battery(ies), negative lead first.
  5. Open the junction box; disconnect the controller at P1, J15, and J16.
  6. Models ECD/EFCD, EGD/EFGD, EGZD only: disconnect the CO sensor harness at the 4-pin connector.
  7. Remove four controller mounting screws and remove the old controller.
  8. ECD/EFCD, EGD/EFGD, EGZD only: install CO sensor module assembly GM46362 on the back of the new controller GM47982.
  9. Install the new controller and secure with the mounting screws.
  10. Reconnect the P1, J15, and J16 connectors; connect the CO sensor harness on applicable models.
  11. Models 10/13/15EG, 10/13/15ERG, 15/30RES, 15/30RYG with S/N before 2053692: cut a 1-in. section of the gray/orange lead entering pin 9 at the ECM connector.
  12. Check that the generator set master switch is in the OFF position.
  13. Reconnect the engine starting battery, negative lead last.
  14. Reconnect power to the battery charger, if equipped.
  15. Check the controller application software version and load the latest application code if necessary.

Extracted from the manufacturer documentation linked to this model. Values are copied as printed; confirm against your unit's manual and serial number.

Voltage reconnection

VoltagePhaseConnectionLeadsNotes
100 VAC11Ph, 2WUu00; 60 Hz
100 VAC11Ph, 3WUu00; 60 Hz
100/200 VAC11Ph, 3WUu08; 60 Hz
110 VAC11Ph, 2WUu05; 50 Hz
110 VAC11Ph, 3WUu05; 50 Hz
110/190 VAC3WyeUu17; 50 Hz
110/220 VAC11Ph, 3WUu07; 50 Hz
110/220 VAC1DoglegUu07; 50 Hz
110/220 VAC3DeltaUu15; 50 Hz
115 VAC11Ph, 2WUu05; 50 Hz
115/200 VAC3WyeUu23; 50 Hz
115/230 VAC11Ph, 3WUu02; 50 Hz
115/230 VAC1DoglegUu06; 50 Hz
115/230 VAC3DeltaUu14; 50 Hz
120 VAC11Ph, 2WUu00; 60 Hz
120 VAC11Ph, 3WUu00; 60 Hz
120/208 VAC3WyeUu11; 60 Hz
120/240 VAC11Ph, 3WUu01; 60 Hz
120/240 VAC1DoglegUu01; 60 Hz
120/240 VAC3DeltaUu10; 60 Hz
127/220 VAC3WyeUu16; 60 Hz
139/240 VAC3WyeUu10; 60 Hz
220 VAC11Ph, 2WUu12; 50 Hz
220/380 VAC3WyeUu19; 60 Hz
230 VAC11Ph, 2WUu02; 50 Hz
230/400 VAC3WyeUu03; 50 Hz
240 VAC11Ph, 2WUu13; 50 Hz
240/416 VAC3WyeUu20; 60 Hz
277/480 VAC3WyeUu04; 60 Hz

Extracted from the manufacturer documentation linked to this model. Values are copied as printed; confirm against your unit's manual and serial number.

Common questions

What size generator is the Kohler 25EFOZD?

The Kohler 25EFOZD is rated 25 kW standby (25.0 kVA).

What fuel does the Kohler 25EFOZD use?

The Kohler 25EFOZD runs on diesel.

Which alternator is fitted to the Kohler 25EFOZD?

The Kohler 25EFOZD uses a Fast-Response X alternator.

Troubleshooting

6

Fault codes

CodeMeaning
High engine temperatureHigh engine temperature shutdown
Low oil pressureLow oil pressure shutdown
Loss of coolantSeawater pump impeller failure shutdown
Overcrank safetyOverspeed
Over/under voltageOver/under voltage
Over/under frequencyOver/under frequency

Fault codes and symptom→remedy steps extracted from this model’s service/owner documentation; verify against the official manual before servicing. Full Kohler 25EFOZD troubleshooting guide (13 entries) →

Parts

77model family
Part #DescriptionQtySystem
229125V-Belt (Seawater Pump)2Belt Amazon $53.99 eBay $22.07 FridayParts $62.70
229826Seawater Pump Impeller Kit4Impeller Amazon $27.95 eBay $45.71 FridayParts $33.59
249989BELT1Belt Amazon $26.40 eBay $19.76
256503BELT1Belt Amazon $36.99 eBay $18.44
260085ZINC ANODE KIT4Zinc anode kit Amazon eBay $16.99
267987FILTER, PRIMARY FUEL1Fuel filter Amazon $10.64 eBay $14.99 KuduParts $18.00
276148BELT1Belt Amazon eBay
359771FILTER, OIL1Oil filter Amazon $64.99 eBay $22.46 FridayParts $66.23
359978IMPELLER REPAIR KIT1Impeller FridayParts $66.23
363205BELT1Belt Amazon $36.26 eBay $25.11
52 050 02-SFilter, oil8Oil filter Amazon $22.70 eBay
ED0021752800-SOil FilterOil filter Amazon $21.95 eBay $22.90 FridayParts $19.99
ED0021752850-SOil Filter4Oil filter Amazon $23.95 eBay $24.95
ED0021752880-SFuel Filter Element4Fuel filter Amazon $13.88 eBay $49.95 KuduParts $14.00
ED0021753200-SFuel Filter ElementFuel filter Amazon $68.80 eBay $17.99 FridayParts $68.86
GM15402BELT1Belt Amazon eBay $34.50
GM18704BELT1Belt Amazon eBay
GM18793IMPELLER REPAIR KIT1Impeller Amazon $69.60 eBay $49.95
GM18808FILTER, SECONDARY FUEL1Fuel filter Amazon eBay $20.00
GM18821FILTER, PRIMARY FUEL1Fuel filter Amazon eBay $49.99
GM28351Filter, oil1Oil filter Amazon $25.85 eBay $19.46
GM32112-KA1Oil pressure sender kit (also -KP1)Sensor buy
GM32359Filter, fuel1Fuel filter Amazon $22.24 eBay $26.87 KuduParts $20.00
GM32809Fuel Filter1Fuel filter Amazon $57.96 eBay $26.25
GM34570Fuel Filter (gasoline)1Fuel filter Amazon $21.55 eBay $34.05
GM35299-KA1Sender kit (also -KP1)Sensor buy
GM35825BELT1Belt Amazon eBay $133.60
GM35826Spark plug4Spark plug Amazon eBay $13.00
GM39266Fuse: Controller, Fuel Pump, and Fuel Shutoff Solenoid (F2) 20 Amp1Fuel pump Amazon eBay $14.88
GM45891-KA1OP and WT sender kitSensor buy
GM46180SPARK PLUG2Spark plug Amazon eBay $15.14
GM46362CO sensor module assembly1Sensor buy
GM47465Filter, oil1Oil filter Amazon $13.66 eBay $23.52 FridayParts $20.19
GM48014BELT, SEAWATER PUMP1Belt buy
GM48727FILTER, PRIMARY FUELFuel filter Amazon $21.88 eBay $24.99
GM48728FILTER, SECONDARY FUEL1Fuel filter Amazon eBay $100.76
GM48729FILTER, PRIMARY FUEL1Fuel filter Amazon $28.55 eBay $24.99
GM48730FILTER, SECONDARY FUEL4Fuel filter Amazon eBay $25.50
GM48731FILTER, OIL4Fuel filter element Amazon $20.01 eBay $49.99
GM50263FILTER, PRIMARY FUEL (Includes primary and secondary filter elements)1Fuel filter Amazon $148.00 eBay $99.99
GM50552-KA1Oil pressure sender kitSensor buy
GM50644Seawater Pump Impeller KitImpeller Amazon $31.00 eBay $30.00
GM53040BELT, SEAWATER PUMP1Belt Amazon $49.73 eBay $19.94
GM77091BELT, SEAWATER PUMP1Belt buy
GM88686BELT1Belt Amazon eBay $43.03
GM90645V-Belt (Seawater Pump)Belt Amazon eBay $30.30
GM91974FUEL FILTER KIT, PRIMARY/SECONDARY1Fuel filter Amazon eBay
GM98756IMPELLER REPAIR KIT4Spark plug Amazon eBay
GM98801BELT1Belt Amazon eBay
X-6348-6DECAL12Decals Amazon eBay
X-6348-9DECAL1Decals buy
223316Fuse, 10 A, 250 V1Service part / kit Amazon $171.06 eBay $31.37
239282Brush2Service part / kit Amazon eBay $37.28
239298Fuse: Customer Connection (F3) 5 Amp1Service part / kit Amazon eBay $7.74
243273Fuse, 3 amp5Service part / kit Amazon eBay
262389Fuse, 25 amp1Service part / kit Amazon eBay $14.83
267928ZINC ANODE KIT1Service part / kit buy
283645Fuse, 15 amp5Service part / kit Amazon eBay
344835CONTAINER1Service part / kit buy
352142ZINC ANODE KIT1Service part / kit Amazon $38.07 eBay $26.09
358337Fuse: Auxiliary Winding (F1) 10 Amp1Service part / kit Amazon $101.99 eBay $45.17
ED0090802150-SZinc Anode4Service part / kit Amazon eBay $60.67
ED0090802840-SZinc Anode4Service part / kit Amazon eBay $92.76
GM28483SCR moduleService part / kit FridayParts $258.90
GM28707Controller Assy ADC 21001Service part / kit buy
GM32337-KP1Remote Digital Gauge for MarineService part / kit buy
GM32337-KP2Remote Digital Gauge for Mobile and Residential/CommercialService part / kit buy
GM42037Controller Assy ADC 21001Service part / kit buy
GM46035-KP1Three-Inch Digital GaugeService part / kit buy
GM46308-KP1Electronic governor kitService part / kit buy
GM47164-KP1Electronic governor kitService part / kit buy
GM47427FUSE, 20-AMP1Service part / kit buy
GM47982Controller Assy ADC 21001Service part / kit buy
GM50822-KP1Two-Inch Digital GaugeService part / kit buy
GV15402CIRCUIT BREAKER, 10-AMP1Service part / kit buy
GV42337FUSE, 10-AMP5Service part / kit buy
GV42339FUSE, 25-AMP5Service part / kit buy

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.

Fuel consumption

RatingLoadL/hgal/h
25%3.20.84
50%4.81.28
75%6.61.74
100%8.92.35
Standby25%3.20.84
Standby50%4.81.28
Standby75%6.61.74
Standby100%8.92.35

Available documents

Spec sheet (Kohler)Reference (Kohler)Reference — Marine pocket guide (Kohler)Reference — PleasureCraft SpecificationSheet (Kohler)Parts manual (Kohler)Parts manual — 2017-Sea-Spares-Brochure-g12202 (Kohler)Service manual — tt1364 (Kohler)