Specifications
| Fuel | natural gas |
|---|---|
| Standby power | 149 kW |
| Prime power | 135 kW |
Filters & service parts
model family| Item | Spec | Capacity | Part # | Interval | |
|---|---|---|---|---|---|
| Fuel filter | — | ||||
| Oil filter | — | ||||
| Belt | — | ||||
| Coolant | — | ||||
| Oil | — | ||||
| Spark plug | — |
Compiled from this model's family documentation — may include parts for closely-related variants. Confirm the exact part for your serial number.
Service specifications
34| Type | Item | Value | Unit | Condition |
|---|---|---|---|---|
| Other | Compression ratio | 10.5:1 | ||
| Other | Compression ratio | 10.5:1(1); 8.5:1(2) | ||
| Other | Compression ratio | 10:1(1); 8.5:1(2) | ||
| Other | Compression ratio | 11:1(1); 8.5:1(2) | ||
| Other | Compression ratio | 12:1; 10:1; 8.5:1 | ||
| Other | Compression ratio | 8.5:1 | ||
| Other | Engine standby/prime power (W/Fan / W/O Fan) | -- | kW | 60 Hz, 1800 RPM, 0.8 PF |
| Other | Engine standby/prime power (W/Fan / W/O Fan) | 10.5:1: 120/128/108/117; 8.5:1: 111/119/101/109 | kW | 60 Hz, 1800 RPM, 0.8 PF |
| Other | Engine standby/prime power (W/Fan / W/O Fan) | 10.5:1: 72/77/65/70; 8.5:1: 66/71/60/64 | kW | 60 Hz, 1800 RPM, 0.8 PF |
| Other | Engine standby/prime power (W/Fan / W/O Fan) | 105/113/95/103 (both CRs) | kW | 60 Hz, 1800 RPM, 0.8 PF |
| Other | Engine standby/prime power (W/Fan / W/O Fan) | 10:1: 154/162/139/147; 8.5:1: 150/157/135/143 | kW | 60 Hz, 1800 RPM, 0.8 PF |
| Other | Engine standby/prime power (W/Fan / W/O Fan) | 10:1: 178/186/159/166; 8.5:1: 168/175/151/159 | kW | 60 Hz, 1800 RPM, 0.8 PF |
| Other | Engine standby/prime power (W/Fan / W/O Fan) | 10:1: 222/230/169/177; 8.5:1: 205/213/158/166 | kW | 60 Hz, 1800 RPM, 0.8 PF |
| Other | Engine standby/prime power (W/Fan / W/O Fan) | 10:1: 278/288/252/262; 8.5:1: 265/275/240/250 | kW | 60 Hz, 1800 RPM, 0.8 PF |
| Other | Engine standby/prime power (W/Fan / W/O Fan) | 10:1: 434/456/389/410; 8.5:1: 415/437/372/393 | kW | 60 Hz, 1800 RPM, 0.8 PF |
| Other | Engine standby/prime power (W/Fan / W/O Fan) | 11:1: 223/235/187/200; 8.5:1: 210/223/178/191 | kW | 60 Hz, 1800 RPM, 0.8 PF |
| Other | Engine standby/prime power (W/Fan / W/O Fan) | 11:1: 241/254/212/224; 8.5:1: 218/230/204/216 | kW | 60 Hz, 1800 RPM, 0.8 PF |
| Other | Engine standby/prime power (W/Fan / W/O Fan) | 12:1: 102/105/93/95; 10:1: 97/100/87/90; 8.5:1: 91/94/81/84 | kW | 60 Hz, 1800 RPM, 0.8 PF |
| Other | Engine standby/prime power (W/Fan / W/O Fan) | 12:1: 125/128/113/116; 10:1: 117/120/106/109; 8.5:1: 110/112/99/102 | kW | 60 Hz, 1800 RPM, 0.8 PF |
| Other | Engine standby/prime power (W/Fan / W/O Fan) | 38/41/34/37 | kW | 60 Hz, 1800 RPM, 0.8 PF |
| Other | Engine standby/prime power (W/Fan / W/O Fan) | 60/64/54/58 | kW | 60 Hz, 1800 RPM, 0.8 PF |
| Other | Engine standby/prime power (W/Fan / W/O Fan) | CLD/527/CLD/479 | kW | 60 Hz, 1800 RPM, 0.8 PF |
| Other | Engine standby/prime power (W/Fan / W/O Fan) | CLD/570/CLD/518 | kW | 60 Hz, 1800 RPM, 0.8 PF |
| Other | Engine standby/prime power (W/Fan / W/O Fan) | CLD/618/CLD/561 | kW | 60 Hz, 1800 RPM, 0.8 PF |
| Other | Engine standby/prime power (W/Fan / W/O Fan) | CLD/680/CLD/618 | kW | 60 Hz, 1800 RPM, 0.8 PF |
| Other | Engine standby/prime power (W/Fan / W/O Fan) | CLD/720/CLD/654 | kW | 60 Hz, 1800 RPM, 0.8 PF |
| Other | Engine standby/prime power (W/Fan / W/O Fan) | CLD/788/CLD/716 | kW | 60 Hz, 1800 RPM, 0.8 PF |
| Pressure | SAE J1349 test condition: barometric pressure | 29.61 | in. Hg | 100 kPa; 300 ft (91 m) altitude |
| Pressure | SAE J1349 test condition: water pressure | 0.30 | in. Hg | 1 kPa |
| Temperature | Rating note (1): water temperature to aftercooler, or use of air-to-air aftercooler with 100 F or lower air temperature to the radiator | 32 | C (90 F) | applies to 10.5:1 / 10:1 / 11:1 note-(1) ratings |
| Temperature | Rating note (2): water temperature to aftercooler, or use of air-to-air aftercooler with 130 F or lower air temperature to the radiator | 54 | C (130 F) | applies to 8.5:1 note-(2) ratings |
| Temperature | Rating note (3): water temperature to aftercooler, or use of air-to-air aftercooler with 110 F or lower air temperature to the radiator | 32 | C (90 F) | applies to 10.5:1 note-(3) ratings |
| Temperature | Rating note (4): water temperature to aftercooler, or use of air-to-air aftercooler with 130 F or lower air temperature to the radiator | 54 | C (130 F) | applies to 8.5:1 note-(4) ratings |
| Temperature | SAE J1349 test condition: inlet air temperature | 77 | F | 25 C |
Extracted from the manufacturer documentation linked to this model. Values are copied as printed; confirm against your unit's manual and serial number.
Recommended fluids
| Fluid | Grade | Standard | Ambient | Capacity | Notes |
|---|---|---|---|---|---|
| Fuel | dry processed natural gas | 905 BTU per standard cubic foot (33.72 kJ/l) lower heating value, used for the tabulated ratings; deration may be required due to altitude, temperature, type of fuel or use of a catalytic converter |
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
How many kW is the Cummins/Onan G 12?
The Cummins/Onan G 12 is rated 149 kW standby.
Which engine powers the Cummins/Onan G 12?
The Cummins/Onan G 12 is powered by the Cummins/Onan G12 engine.
What kind of fuel does the Cummins/Onan G 12 run on?
The Cummins/Onan G 12 runs on natural gas.
Parts
3| Part # | Description | Qty | System | |
|---|---|---|---|---|
| 3803897 | Non-Shielded Spark Plugs | Non shielded spark plug | Amazon eBay | |
| G12-425 | Carburetor | Carburetor | eBay | |
| S-40XLBEX13 | Shielded Spark Plugs | Shielded spark plug | Amazon eBay |
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.
Available documents
Engine spec — gdrivehp (Cummins/Onan)Engine spec — gdrivekwe (Cummins/Onan)Service manual — GTA (Cummins/Onan)