Specifications
| Fuel | diesel |
|---|---|
| Frequency | 50.0 Hz |
| Standby power | 2400 kW |
| Standby kVA | 3000 |
| Prime power | 2200 kW |
Engine
| Displacement | 78.0 L |
|---|---|
| Aspiration | Turbocharged and low temperature after-cooled |
| Rated speed | 1500 rpm |
Filters & service parts
model family| Item | Spec | Capacity | Part # | Interval | |
|---|---|---|---|---|---|
| Air filter | — | ||||
| Fuel filter | — | ||||
| Oil filter | — | 1500 hr | |||
| Battery | — | ||||
| 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 intervals
4| Item | Action | Hours | Months | Notes |
|---|---|---|---|---|
| Lubricating oil | Test | 250 hr | 6 mo | First service — For high horsepower engines with Eliminator™ oil filter option: take oil samples every 250 hours and analyze per Cummins Engine Oil Recommendations Bulletin 3810340; repeat for at least three oil change intervals. |
| ELIMINATOR self cleaning filter core | Other | 1500 hr | Requires servicing only every 1,500 hours. Saves up to 90% of lube system maintenance costs and increases productivity. | |
| valve clearance | Check | 2000 hr | B-Series (4BT3.3): valve clearance checks not required for 2000 hours, twice the industry standard | |
| engine overhaul | Other | 20000 hr | QSK23-Series: expected life cycle to 20,000 hours before first overhaul |
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
7| Type | Item | Value | Unit | Condition |
|---|---|---|---|---|
| Other | DB9F-DB9M serial cable length (Part Number 4918418) | 1.83 | M | |
| Other | Extension DB9F to DB9M length (Part Number 3162851) | 30.48 | M | |
| Other | INLINE™5 datalink adapter current requirement | 250 | mA | at +8 VDC to +50 VDC |
| Other | USB cable length (Part Number 4918419) | 2 | M | |
| Other | USB cable length (Part Number 4918591) | 5 | M | |
| Voltage | INLINE™5 datalink adapter supply voltage (maximum) | +50 | VDC | power lamp fast flashing indicates greater than maximum |
| Voltage | INLINE™5 datalink adapter supply voltage (minimum) | +8 | VDC | power lamp slow flashing indicates less than minimum |
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 |
|---|---|---|---|---|---|
| Engine oil | Cummins Engine Oil Recommendations Bulletin 3810340 | Used to analyze oil samples for high horsepower engines with Eliminator™ oil filter option. | |||
| Fuel | B100 biodiesel | ASTM D6751 | Must conform prior to blending; revised to include a cold soak test; stability requirement still in effect. | ||
| Fuel | B20 biodiesel blend | ASTM D7467 | Applies to biodiesel blends B6–B20; includes oxidation stability requirement; replaces Cummins' previous EMA B20 specification requirement. Must be purchased from a BQ9000 Certified Marketer; B100 must be sourced from a BQ9000 Accredited Producer. | ||
| Fuel | B5 biodiesel | All Cummins automotive and industrial engines are compatible with B5 biodiesel. | |||
| Fuel | biodiesel (Europe) | EN 14214 | Published by CEN, European Committee for Standardization. Equivalent biodiesel specifications required internationally. |
Extracted from the manufacturer documentation linked to this model. Values are copied as printed; confirm against your unit's manual and serial number.
Procedures
3Connect the INLINE™5 Datalink Adapter to a Personal Computer installation
⚠ A fully populated USB cable, Part Number 4918419, or DB9F-DB9M serial cable, Part Number 4918418, must be used.
- Connect the DB9F-DB9M serial cable, Part Number 4918418, or USB cable, Part Number 4918419, to the computer.
- Connect the other end of that cable to the INLINE™5 datalink adapter, Part Number 3165033.
- Supply +8 VDC to +50 VDC at 250mA through the OEM connector or a separate power source.
- Connect the appropriate datalink cable to the INLINE™5 datalink adapter, Part Number 3165033.
- Connect the other end of the datalink cable to the vehicle cab or engine compartment datalink connector.
- Launch the electronic service tool application software.
Oil sampling for high horsepower engines with Eliminator™ oil filter option maintenance
- Take oil samples every 250 hours of operation.
- Analyze samples according to Cummins Engine Oil Recommendations Bulletin 3810340.
- Repeat for at least three oil change intervals to ensure consistent oil behavior.
Switching from petrodiesel to B20 on used engines maintenance
⚠ B20 has a solvent nature and may clean the vehicle fuel tank and lines.
- Install new fuel filters when switching to B20.
- Replace fuel filters at half the standard interval for the next two fuel filter changes.
- After the initial period, revert to intervals specified in the O & M manual.
- For EPA 2007 on-highway midrange engines, sample oil for the first 6 months to monitor fuel dilution.
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 QSK78?
The Cummins/Onan QSK78 is rated 2400 kW standby (3000.0 kVA).
What engine is in the Cummins/Onan QSK78?
The Cummins/Onan QSK78 is powered by the Cummins/Onan QSK78-G9 engine.
What fuel does the Cummins/Onan QSK78 use?
The Cummins/Onan QSK78 runs on diesel.
What is the continuous rating of the Cummins/Onan QSK78?
The Cummins/Onan QSK78 is rated 2200 kW prime (2750 kVA), against 2400 kW standby.
Parts
47| Part # | Description | Qty | System | |
|---|---|---|---|---|
| A049E322 | Belt (Matched Set) | 1 | Belt | Amazon eBay |
| 550224 | grease | 0.09 kg minimum | Service part / kit | Amazon eBay |
| 550226 | ear mesh grease | 1.12 kg | Service part / kit | Amazon eBay FridayParts $39.99 |
| 5572840 | Cylinder Head Lifting Handle Kit | Service part / kit | Amazon eBay | |
| 5572936 | Threaded Fitting Clean Care Kit | Service part / kit | Amazon eBay | |
| 5573037 | Camshaft Removal & Installation Kit | Service part / kit | Amazon eBay | |
| 5573156 | Retaining Compound | Service part / kit | Amazon eBay | |
| A023-259 | Coupling, Flexible | 1 | Service part / kit | Amazon eBay |
| A023-270 | Coupling, Flexible | 1 | Service part / kit | Amazon eBay |
| A023-271 | Coupling, Flexible | 1 | Service part / kit | Amazon eBay |
| A023-272 | Coupling, Flexible | 1 | Service part / kit | Amazon eBay |
| A023-4121-01 | Screw, Hex Head (M12 x 1.75 x 55) | 16 | Service part / kit | Amazon eBay |
| A023-4121-02 | Screw, Hex Head (M12 x 1.75 x 55) | 16 | Service part / kit | Amazon eBay |
| A023-4121-03 | Screw, Hex Head (M12 x 1.75 x 55) | 16 | Service part / kit | Amazon eBay |
| A023-4121-04 | Screw, Hex Head (M12 x 1.75 x 55) | 16 | Service part / kit | Amazon eBay |
| A023-4121-05 | Screw, Hex Head (M12 x 1.75 x 55) | 16 | Service part / kit | Amazon eBay |
| A023-4121-06 | Screw, Hex Head (M12 x 1.75 x 55) | 8 | Service part / kit | Amazon eBay |
| A023-4126-01 | Screw, Hex Head (M12 x 1.75 x 55) | 8 | Service part / kit | Amazon eBay |
| A023-4126-02 | Screw, Hex Head (M12 x 1.75 x 55) | 8 | Service part / kit | Amazon eBay |
| A023-4126-03 | Screw, Hex Head (M12 x 1.75 x 55) | 8 | Service part / kit | Amazon eBay |
| A023-4126-04 | Screw, Hex Head (M12 x 1.75 x 55) | 8 | Service part / kit | Amazon eBay |
| A023-4126-05 | Screw, Hex Head (M12 x 1.75 x 55) | 8 | Service part / kit | Amazon eBay |
| A023-4918-02 | Skid | 1 | Service part / kit | Amazon eBay |
| A023-4919-02 | Skid | 1 | Service part / kit | Amazon eBay |
| A023-4933-02 | Pad, Jacking − “E”, “F” and “G” Generators | 8 | Service part / kit | Amazon eBay |
| A023-5083-02 | Skid | 1 | Service part / kit | Amazon eBay |
| A023-5130-02 | Crossmember, Skid − Upper | 1 | Service part / kit | Amazon eBay |
| A023-5131-02 | Crossmember, Skid − Lower | 1 | Service part / kit | Amazon eBay |
| A023-5132-02 | Plate, Skid | 1 | Service part / kit | Amazon eBay |
| A023-6308 | Screw, Hex Head (M36 x 4 x 100) | 4 | Service part / kit | Amazon eBay |
| A023-6311 | Screw, Hex Head (M20 x 1.5 x 45) | 8 | Service part / kit | Amazon eBay |
| A030A823 | Nut (M10) | 1 | Service part / kit | Amazon eBay |
| A030W925 | Pipe, J/W Bottom − Assy. | 1 | Service part / kit | Amazon eBay |
| A030W929 | Pipe, LTA L/H | 1 | Service part / kit | Amazon eBay |
| A030W930 | Pipe, LTA L/H | 1 | Service part / kit | Amazon eBay |
| A030W931 | Pipe, LTA L/H | 1 | Service part / kit | Amazon eBay |
| A030W936 | Pipe, LTA R/H | 1 | Service part / kit | Amazon eBay |
| A030W939 | Pipe, LTA R/H | 1 | Service part / kit | Amazon eBay $188.05 |
| A030W940 | Pipe, LTA R/H | 1 | Service part / kit | Amazon eBay |
| A041E813 | U-Bolt | 1 | Service part / kit | Amazon eBay |
| A041E815 | Bracket, Pipe Support | 1 | Service part / kit | Amazon eBay |
| A041E817 | Pully | 1 | Service part / kit | Amazon eBay $641.95 |
| A049D324 | Clamp, U-Bolt | 1 | Service part / kit | Amazon eBay |
| A049D330 | Screw, Set (M8 x 25) | 2 | Service part / kit | Amazon eBay |
| A049D335 | Bush, Taperlock | 1 | Service part / kit | Amazon eBay |
| A049W329 | Washer (M10) | 1 | Service part / kit | Amazon eBay |
| APCH-1007-12 | Bulletin 5600277 | Service part / kit | 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 — 0032276 (Cummins/Onan)Spec sheet — 0032488 (Cummins/Onan)Spec sheet — QSK78-G9 (Cummins/Onan)Reference — 0032425 (Cummins/Onan)Reference — 0070393Reference — CUMMINS-GENERATOR-ENGINES-CATALOG (Cummins/Onan)Reference — Features 8.8.1Reference — Schedule Technical2012 (Cummins/Onan)Parts manual — 908-0200 Cummins QSK78 Engine Parts Manual (7-2014) (Cummins/Onan)Parts manual — {5bc4040d-d72a-4ebb-81b9-034afcefa4a9} Cummins Mechanical Electrical Service Tools June 2019Service manual — 908-0106 Cummins QSK78 Genset Installation & Alignment manual (10-2009) (Cummins/Onan)Service manual — 908-0107 Cummins Power Command Radiator Addendum (1-2013) (Cummins/Onan)Service manual — 908-0600 Cummins QSK78 Engine Installation Manual (2-2015) (Cummins/Onan)Service manual — B20BiodieselFAQJan2009 (Cummins/Onan)Service manual — ServiceInstructions5 (Cummins/Onan)
This page was generated from the 15 manufacturer documents above by automated extraction; every figure shown is copied from one of them. How the data is compiled.