Electrical and Systems
RV and Fleet Generator Service, Repair and Replacement
Typical range
$400 to $8,500+
Shop hours
2 to 35+
Labor rate
$260/hr
The short answer
Generator service covers scheduled maintenance, no-start and no-output diagnosis, carburetor and fuel system work, and full replacement on Onan and Cummins units. Work runs $400 to $8,500 and up, or 2 to 35 plus hours at $260 per hour plus parts.
01
What this work actually involves
Most generator failures we see are not mechanical wear. They are storage failures. A coach that sits eleven months a year in Yorba Linda, Corona, or Riverside gums its carburetor jets with varnished ethanol fuel, and then the owner cranks it flat trying to start it before a trip. Gasoline Onan units are the worst offenders because the jets are small and the float bowl sits low. Diesel units fail differently, usually air in the fuel line or an injector that has sat dry, but the root cause is the same lack of exercise under load.
The second failure category is heat and load. A generator mounted in a sealed compartment on a coach parked in Indio or Palm Desert is drawing 120 degree intake air before it even starts working. Run two air conditioners off it at that ambient and it will overheat, drop output voltage, and eventually trip its own thermal protection. Owners read low voltage at the outlets as an electrical fault in the coach when the generator is simply running out of margin.
The third is output rather than running. A unit that starts and runs beautifully but produces no 120V usually has a failed voltage regulator, worn brushes, or an open winding, and that is a completely separate repair path from a fuel problem. We test output under a real load bank rather than plugging in a light and calling it good, because a generator can make voltage at no load and collapse at 20 amps.
Systems and brands we work on: Onan, Cummins.
Location: All work is performed at our Yorba Linda facility. We do not offer mobile, roadside, or fleet route service.
02
What the job includes
- Scheduled service including oil, filters, plugs, and air cleaner
- No-start diagnosis covering fuel, spark, compression, and control board
- Carburetor removal, cleaning, rebuild, or replacement on gasoline units
- Diesel fuel system bleeding, filter service, and injector diagnosis
- Voltage regulator, brush, and stator testing on no-output complaints
- Load bank testing of real output at rated amperage
- Start and stop control circuit, remote panel, and wiring repair
- Exhaust system, muffler, and mounting repair or replacement
- Compartment ventilation and intake air path correction
- Full generator replacement and commissioning
03
When you need this service
- Cranks strongly but will not fire after months in storage
- Starts and then dies within thirty seconds under any load
- Runs fine but delivers no 120V at the coach outlets
- Output voltage sags and air conditioners short cycle on hot days
- Surging or hunting engine speed that will not settle
- Black smoke, a fuel smell, or exhaust entering the coach
- Repeated shutdowns on its own thermal or overload protection
04
How we do it, step by step
- 01
Reproduce the failure
We run the unit and watch it fail rather than working from the description. No-start, no-output, and shutdown-under-load are three different repairs and they get confused constantly.
- 02
Fuel and ignition path
On a no-start we verify fuel delivery at the carburetor or injection pump, spark or injection event, and compression before touching the control board.
- 03
Electrical output testing
On a no-output complaint we test the voltage regulator, brushes, and stator windings, then load bank the unit at rated amperage to see whether output holds.
- 04
Thermal and ventilation check
Compartment intake and exhaust path measured. A generator pulling recirculated hot air will never make rated output in low desert conditions no matter what we replace.
- 05
Documented findings and pricing
Photographed findings with measured numbers and a repair-versus-replace comparison, because on older gasoline units a rebuild sometimes exceeds the value of the set.
- 06
Repair and load verification
Parts installed, service intervals reset, and the unit run under load bank at rated output for a sustained period before we call it finished.
05
Pricing and posted rates
| Item | Rate or range | Notes |
|---|---|---|
| Typical job range | $400 to $8,500+ | Varies with extent of damage and parts availability |
| Shop hours | 2 to 35+ | Quoted after teardown, not before |
| Mechanical and electrical labor | $260 per hour | 2026 posted rate |
| Parts | 100% markup under $100, 35% over | Special order parts require a non refundable deposit at order |
| Deposit | 50% at authorization over $2,000 | Additional 25% when parts arrive on jobs over $10,000 |
| Sales tax | 7.75% on parts and materials | Labor is not taxed |
Insurance billed jobs may be billed at carrier negotiated labor rates that differ from the posted retail rates above. See all posted rates.
07
Vehicles we do this work on
Vehicle
Class A Gas Motorhomes
A Class A gas motorhome is a flat-front coach built on a Ford F53 or Workhorse front-engine chassis, typically 28 to 38 feet. Rear
Vehicle
Class A Diesel Pusher Motorhomes
A diesel pusher carries a rear-mounted diesel on a raised-rail air ride chassis, usually 34 to 45 feet with full-body paint and pa
Vehicle
Class C Motorhomes
A Class C is a coach body built onto a cutaway van chassis with a sleeping or storage cabover extending above the factory cab. Tha
Vehicle
Super C Motorhomes
A Super C is a full coach body mounted on a medium duty truck chassis such as a Freightliner M2, International, or Kenworth, with
Vehicle
Toy Hauler Fifth Wheels
A toy hauler fifth wheel carries a cargo garage behind the axles with a full-height rear ramp door. Load behind the axle centerlin
Vehicle
Bus Conversions, Prevost and Marathon
A Prevost, MCI, or Van Hool conversion is a commercial motorcoach shell finished by a second-stage builder such as Marathon, Feath
Vehicle
Mobile Medical Clinics
Mobile medical clinics carry exam rooms, imaging or dental equipment, patient access lifts, and climate control that cannot fail w
08
Questions about generator service and repair
Frequently asked questions
How much does RV generator repair cost?
Work runs $400 to $8,500 and up, or 2 to 35 plus hours at $260 per hour plus parts. A service with a carburetor clean on an accessible gasoline set is at the low end. A full diesel generator replacement with new mounts, exhaust, wiring, and commissioning is at the high end.
My generator will not start after sitting all winter. What is wrong?
Nine times out of ten it is varnished fuel in the carburetor jets on a gasoline unit, or air and stale fuel in the lines on a diesel. Ethanol blended pump gas separates and gums within a few months. The fix is a carburetor clean or rebuild and fresh fuel, and the prevention is running it under load monthly.
It runs but I get no power in the coach. Is that the generator?
It could be the generator output side or it could be the transfer switch. A generator that runs and makes no voltage usually has a failed regulator, worn brushes, or an open winding. A generator making good voltage that never reaches the coach is a transfer switch problem. We test at the generator terminals first to split the two.
How often should I service my generator?
Follow the hour interval in the manual, but the more important habit is running it under at least half load for a couple of hours every month. Generators fail from sitting, not from running. Exercising it circulates oil, keeps the carburetor wet, and surfaces a problem in your driveway instead of at a campground.
Do you replace generators as well as repair them?
Yes. Full replacement including mounts, exhaust, fuel connections, control wiring, and commissioning is done in the shop. On older gasoline sets where parts availability is poor, we price the rebuild against the replacement so you can compare real numbers rather than guessing.
09
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Ready to move on generator service and repair? Bring it to Yorba Linda.