Specifications
| Fuel | diesel |
|---|---|
| Frequency | 60.0 Hz |
| Voltage options | 120 V, 240 V |
| Phase | 1 |
| Rated current | 104.0/52.0 A |
| Sound level | 68.0 dBA @ 3 m |
Filters & service parts
model family| Item | Spec | Capacity | Part # | Interval | |
|---|---|---|---|---|---|
| Air filter | Green Label Parts air filter with foam pre-cleaner; clean by tapping on flat surface; never wash in solvents or blow out with air hose | — | 50 hr | ||
| Fuel filter | Change on a regular maintenance schedule; removes debris that clogs carburetor jets | — | |||
| Oil filter | Green Label Parts oil filters with bypass valve; change when changing oil | — | |||
| Battery | Clean & check battery & connections; more often in hot weather | — | 500 hr | ||
| Coolant | 50/50 mixture of ethylene glycol based antifreeze and clean soft/distilled water | — | |||
| Oil | OnaMax SAE-30 or SAE 15W-40; API SJ/SL/SM (gasoline) or CF/CF-4/CG-4/CH-4/CI-4/CJ-4 (diesel) | 0.6 L | — | 50 hr | |
| Spark plug | Green Label resistive original equipment spark plugs; non-resistive plugs can cause shutdowns without fault codes | — |
Compiled from this model's family documentation — may include parts for closely-related variants. Confirm the exact part for your serial number.
Service intervals
7| Item | Action | Hours | Months | Notes |
|---|---|---|---|---|
| Oil level | Check | 8 hr | Check oil daily or every 8 hours of operating time; perform a general inspection daily per Operator's Manual | |
| Engine oil | Change | 50 hr | First service — Break-in: change engine oil after the first 20-50 hours of operation (RV QG/RV QG RM); perform at least once a year | |
| Battery & connections | Clean | 1 mo | Clean & check battery & connections; perform more often in hot weather | |
| Oil/oil filter - Quiet Diesel 10000/12500 | Change | First service — Break-in then repeat (footnotes 1-4, 2-4) | ||
| Oil/oil filter - Quiet Diesel 5500 | Change | First service — Break-in then repeat (footnotes 1-4, 2-4) | ||
| Oil/oil filter - Quiet Diesel 7500/8000 | Change | First service — Break-in then repeat (footnotes 1-4, 2-4) | ||
| Spark arrester | Clean | 1 mo | Clean arrester; perform sooner if engine performance deteriorates |
Extracted from the manufacturer documentation linked to this model. Values are copied as printed; confirm against your unit's manual and serial number.
Service specifications
3| Type | Item | Value | Unit | Condition |
|---|---|---|---|---|
| Other | Power output change with altitude | 3.5 | % decrease per 1000 ft increase | typical power output change based on ambient conditions |
| Other | Power output change with temperature | 1 | % decrease per 10 degF increase | typical power output change based on ambient conditions |
| Temperature | Ambient conditions for rated power output | 77 | degF | with muffler and RV enclosure, per ISO 8528-1; altitude 500 ft (152.4 m), 99 kPa dry |
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 |
|---|---|---|---|---|---|
| Coolant | 50/50 ethylene glycol based antifreeze and water | Mix thoroughly before adding; use clean soft tap water, distilled water or pure rain; select high quality antifreeze with corrosion inhibitors | |||
| Engine oil | SAE 10W-30 / 10W-40 / 0W-30 / 5W-30 | Use viscosity chart to select grade for expected ambient temperature range; avoid mixing grades or brands | |||
| Engine oil | SAE 15W-40 | API CF, CF-4, CG-4, CH-4, CI-4 or CJ-4 (diesel) | OnaMax 15W-40 #326-5336; multi-grade recommended year-round in liquid-cooled engines; synthetic oil not recommended | ||
| Engine oil | SAE-30 | API SJ, SL or SM (gasoline) | OnaMax SAE-30 #326-5339; preferred summer grade for optimum oil consumption control in air-cooled engines | ||
| Fuel | ASTM No.2-D / No.1-D / No.2-DLS / No.1-DLS / B5 Biodiesel | minimum Cetane number 45 | No.2-D or No.2-DLS above 23 degF; No.1-D or No.1-DLS below 23 degF; B5 Biodiesel above 50 degF; use No.1 diesel below 32 degF and during long light-load periods; cloud point at least 10 degF below lowest expected fuel temperature | ||
| Fuel | Diesel | ||||
| Fuel | HD-5 grade liquid propane | at least 90% propane | Fuels other than HD-5 can contain more than 2.5% butane causing poor vaporization/starting below 32 degF | ||
| Fuel | Regular unleaded gasoline | Ethanol blend not more than 10% ethanol; methanol blend not more than 5% methanol | Use fresh gas, not more than 30 days old; fuel stabilizer extends fuel life | ||
| Other | Cummins Onan Premium Fuel System Cleaner | 12.0 oz | Treats up to 24 gallons of gasoline; #326-5342 | ||
| Other | OnaFresh GXLP fuel stabilizer | 16.0 oz | Treats 40 gallons of gasoline; #326-5365 |
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 kind of fuel does the Cummins/Onan RV QD 12500 run on?
The Cummins/Onan RV QD 12500 runs on diesel.
How loud is the Cummins/Onan RV QD 12500?
The Cummins/Onan RV QD 12500 is rated at 68.0 dBA at 3 m, per the manufacturer specification sheet.
What voltages is the Cummins/Onan RV QD 12500 available in?
The Cummins/Onan RV QD 12500 is offered in 120 V, 240 V, 1-phase.
Troubleshooting
7Symptoms & remedies
| Symptom | Cause | Remedy |
|---|---|---|
| Fails To Crank | Low battery, Bad battery connection, Blown fuse | Check battery fluid level, Clean & tighten all battery & cable connections, Replace fuse on control panel |
| Cranks But Won’t Start | Fuel below generator pickup level in tank, Fuel supply shutoff valve closed, Carbon deposits on spark plug(s), Low oil level | Add fuel, Fully open fuel supply valve, Remove spark plug(s) and replace, Add oil |
| Exhausting Black Smoke | Dirty air filter | Replace air filter |
| Unit Runs Then Stops, Or Stops When Driving Around A Corner | Low fuel level, Low oil level, Excess oil | Add fuel, Add oil, Reduce engine oil level |
| Unit Starts And Runs, Then Stops When The Start Switch Is Released | Low fluid levels, Possible overheating, Other functional problem | Check & bring all fluids up to the appropriate levels, Check for blocked air flow or other possible causes of overheating, Contact an Cummins Onan Authorized RV Service & Parts Dealer |
| Unit Runs Then Surges | Loose or worn spark plug leads, Defective ignition coil, wiring, or control components, Faulty spark plug, Governor out of adjustment, Combustion air pre-heat malfunction, Carburetor icing, Carburetor varnishing | Check spark plug leads at spark plug & ignition coil, Contact an Cummins Onan Authorized RV Service & Parts Dealer, Remove spark plug & clean or replace, Contact an Cummins Onan Authorized RV Service & Parts Dealer, Contact an Cummins Onan Authorized RV Service & Parts Dealer, Contact an Cummins Onan Authorized RV Service & Parts Dealer |
| Circuit Breaker Trips | Overloaded circuit | Turn-off some of the electrical load, and reset the circuit breaker |
Fault codes and symptom→remedy steps extracted from this model’s service/owner documentation; verify against the official manual before servicing.
Parts
69model family| Part # | Description | Qty | System | |
|---|---|---|---|---|
| 122-0645 | Filter, Oil | 1 | Oil filter | Amazon eBay $11.99 NAPA $9.09 |
| 122-0800 | Oil filter | 1 | Oil filter | Amazon eBay $31.23 FridayParts $39.99 |
| 122-0827 | Oil filter | Oil filter | eBay $17.87 FridayParts $20.19 | |
| 122-0833 | Filter, Oil | 1 | Oil filter | Amazon eBay $19.99 NAPA $9.64 FridayParts $20.19 |
| 122-0893 | Oil filter | Oil filter | eBay $49.99 | |
| 140-0495 | Air Cleaner Element | 1 | Air filter | Amazon eBay $16.99 NAPA $29.20 |
| 140-1220 | Air Cleaner Element | Air filter | Amazon eBay $25.00 | |
| 140-1229 | Air filter | Air filter | eBay | |
| 140-2105 | Oil filter | Oil filter | eBay $44.01 | |
| 140-2379 | Element, Air Cleaner | 1 | Air filter | Amazon eBay $11.59 NAPA $15.71 |
| 140-2609 | Oil filter | Oil filter | eBay $9.99 | |
| 140-2680 | Air filter | Air filter | eBay | |
| 140-2842 | Air filter | Air filter | eBay | |
| 140-2897 | Element, Air Filter | 1 | Air filter | Amazon eBay $19.99 FridayParts $48.61 |
| 140-3071 | Air filter | 1 | Air filter | Amazon eBay $13.50 FridayParts $16.50 |
| 140-3116 | Oil filter | Oil filter | eBay $18.99 FridayParts $48.88 | |
| 140-3280 | Oil filter | Oil filter | eBay $34.03 KuduParts $12.00 FridayParts $14.60 | |
| 140-3295 | Oil filter | Oil filter | eBay $12.79 | |
| 140-3351 | Air filter | 1 | Air filter | Amazon eBay $56.44 |
| 147-0860 | Filter, Fuel for HDKAK and HDKAH (Beginning Spec N) | 1 | Fuel filter | Amazon eBay $19.99 KuduParts $12.00 |
| 148-0898 | Fuel filter | 1 | Fuel filter | Amazon eBay |
| 149-1353 | Filter, Fuel Pump Fuel | 1 | Fuel filter | Amazon eBay $20.98 NAPA $7.27 |
| 149-1914-05 | Fuel Filter Element | 1 | Fuel filter | Amazon eBay $41.25 |
| 149-2106 | Fuel Filter | 1 | Fuel filter | Amazon eBay $34.99 NAPA $61.61 KuduParts $68.00 |
| 149-2137 | Air filter | 1 | Air filter | Amazon eBay $37.20 KuduParts $7.00 |
| 149-2279 | Filter, Fuel | 1 | Fuel filter | Amazon eBay $26.93 KuduParts $31.00 FridayParts $33.04 |
| 149-2333 | Filter, Carburetor Fuel | 1 | Fuel filter | Amazon eBay $10.97 KuduParts $8.00 FridayParts $10.50 |
| 149-2341 | Filter, Fuel | 1 | Fuel filter | Amazon eBay $14.39 |
| 149-2457 | Air filter | Air filter | eBay $11.50 KuduParts $10.00 FridayParts $12.00 | |
| 149-2513 | Filter, Fuel | 1 | Fuel filter | Amazon eBay $36.95 NAPA $31.59 FridayParts $48.61 |
| 149-2629 | Air filter | Air filter | eBay | |
| 149-2648 | Fuel filter (LP) | Fuel filter | eBay $20.00 | |
| 160-1378 | Electronic Ignition | Electronic ignition | Amazon eBay | |
| 167-0237 | Plug, Spark | 2 | Spark plug | Amazon eBay $14.00 NAPA $3.97 |
| 167-0241 | Spark Plugs | 2 | Spark plug | Amazon Amazon eBay $34.86 eBay $17.97 |
| 167-0247 | Spark Plug | 2 | Spark plug | Amazon eBay $5.00 |
| 167-0262 | Spark plug | Spark plug | eBay $12.99 | |
| 167-0263-02 | Plug, Spark | 1 | Spark plug | Amazon eBay $15.68 NAPA $2.23 |
| 167-0272 | Plug, Spark (E1, E2) | 2 | Spark plug | Amazon eBay |
| 167-0275 | Duct, Inlet-Air | 1 | Duct inlet air | Amazon eBay $20.38 |
| 167-0298 | Plug, Spark | 2 | Spark plug | Amazon eBay $9.99 |
| 167-0305 | Fuel filter | Fuel filter | eBay | |
| 167-1602 | Cable, Spark Plug | 2 | Spark plug | Amazon eBay $53.93 |
| 167-1638 | Fuel filter | Fuel filter | eBay | |
| 185-2289 | Glow Plug (12 Volt) | Glow plug | Amazon eBay $24.95 | |
| 185-5421 | Plug, Glow | 2 | Glow plug | Amazon eBay $35.00 |
| 185-5835 | Oil Filter | 1 | Oil filter | Amazon eBay $21.78 NAPA $3.59 FridayParts $20.19 |
| 185-5990 | Glow Plug (12 Volt) | 1 | Glow plug | Amazon eBay $55.74 |
| 185-6623 | Glow plug | Glow plug | Amazon eBay $39.99 | |
| 185-7444 | Filter, Oil | 1 | Oil filter | Amazon eBay $29.95 NAPA $9.09 KuduParts $11.00 FridayParts $13.23 |
| 187-1000 | Filter, Oil | 1 | Oil filter | Amazon eBay $63.20 FridayParts $20.19 |
| 187-1289 | Glow plug | 3 | Glow plug | Amazon eBay |
| 326-5336 | OnaMax engine oil, 15W-40, 32 oz. bottle | Fluid | eBay $43.24 | |
| 326-5339 | OnaMax engine oil, SAE-30, 32 oz. bottle | Fluid | eBay $109.19 | |
| 326-5365 | OnaFresh GXLP fuel stabilizer, 16 oz. bottle | Fluid | eBay | |
| 420-0577 | Oil filter wrench (cup-type) | Oil filter | Amazon eBay $19.68 | |
| 122-0836 | Tune-up kit (electronic ignition) | Service part / kit | eBay $18.99 FridayParts $20.28 | |
| 160-0002 | Point Set, Breaker | 1 | Service part / kit | Amazon eBay $19.99 NAPA $28.64 |
| 160-1154 | Point Set, Breaker | 1 | Service part / kit | Amazon eBay |
| 160-1328-01 | Tune-up kit | Service part / kit | eBay | |
| 160-1348-01 | Tune-up kit | Service part / kit | eBay | |
| 160-1349-01 | Tune-up kit (electronic ignition) | Service part / kit | eBay | |
| 167-1615-01 | Cable, Spark Plug 9' | 1 | Service part / kit | Amazon eBay |
| 167-1616-01 | Plug wire | Service part / kit | eBay $60.00 | |
| 167-1625-01 | Plug wire, 9 in. | Service part / kit | Amazon eBay | |
| 167-1625-02 | Plug wire, 23 in. | Service part / kit | eBay | |
| 326-5278 | 4C Combustion Chamber and Carburetor Cleaner, 12-oz. aerosol can | Service part / kit | eBay | |
| 326-5288 | Onagard storage fogging spray, 12-oz. aerosol can | Service part / kit | eBay | |
| 326-5342 | Cummins Onan Premium Fuel System Cleaner, 12-oz. bottle | Service part / kit | eBay |
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
| Rating | Load | L/h | gal/h |
|---|---|---|---|
| 0.76 | 0.2 | ||
| 50% | 1.14 | 0.3 | |
| 100% | 1.51 | 0.4 |
Available documents
Spec sheet (Cummins/Onan)Owner's manual — Onan - Generator Handbook (2019) (Cummins/Onan)Parts manual — F-1123 Cummins-Onan RV Generator Handbook (08-2007) (Cummins/Onan)
This page was generated from the 3 manufacturer documents above by automated extraction; every figure shown is copied from one of them. How the data is compiled.