Electrical and Power
RV and Fleet Generator Repair Serving Long Beach
About 10 min left
OCRV Center services and repairs RV and commercial generators including Onan and Cummins units, covering fuel system faults, ignition, cooling, control boards and full overhaul. Generator work runs $400 for a service to $8,500 for a major overhaul or replacement installation.
The single most common reason an RV generator will not start is that it has not been run in eight months. Gasoline degrades, the light fractions evaporate, and what stays behind is a varnish that blocks the tiny passages in a carburetor. That is not a broken generator. That is a generator that was stored wrong.
The second most common reason is that it has been run under no load for years. Generators are designed to work, and running one with nothing switched on causes wet stacking, where unburned fuel accumulates in the exhaust and glazes the cylinder walls.
Fuel System Faults and Varnish
On gasoline units the carburetor is the usual failure point after storage. Main jets and idle circuits are small enough that a modest amount of varnish blocks them entirely, producing a unit that cranks, may fire briefly on the primer, and will not run.
Cleaning is often successful, though on units that have sat for years the correct answer is frequently a carburetor replacement, because gaskets and diaphragms have hardened alongside the varnish. Diesel units suffer differently, mostly from injector and lift pump problems and from algae growth in tanks that have sat with fuel in them.
Storage Practices That Prevent This
Run the generator under a real load for two hours monthly. That single habit prevents both varnish and wet stacking and is the highest value maintenance available on the unit.
For extended storage, either run the carburetor dry or treat the fuel with a stabilizer. Both work. Doing neither is what fills our shop with generators every spring.
Load Testing and Diagnosis
A generator that starts and runs is not necessarily a healthy generator. Many faults only appear under load, including weak output, voltage sag, frequency drift and overheating.
We load test rather than simply confirming it starts, which is what catches a unit that will start in your driveway and then fault the moment two air conditioners come on at a campsite.
Cooling, Exhaust and Enclosure
Generator compartments accumulate debris, and rodent nesting in a generator enclosure is extremely common on stored coaches. Both restrict cooling airflow and cause overheating shutdowns that get misdiagnosed as electrical faults.
Exhaust systems corrode, and an exhaust leak in an enclosed compartment is a genuine carbon monoxide hazard rather than a maintenance nuisance. We inspect the full exhaust path on every generator service.
Overhaul Versus Replacement
On a unit with high hours and low compression, overhaul and replacement land close enough in cost that it becomes a judgment call about the rest of the coach.
We measure compression and evaluate the control board and wiring condition before recommending either. Pouring an overhaul into a unit with a failing control board and corroded harness is how owners end up paying twice.
What Is Included
- Load testing rather than a simple start and run check
- Fuel system inspection including tank condition on units that sat
- Compression measured before any overhaul recommendation
- Cooling airflow path cleared and rodent nesting removed
- Full exhaust path inspected for leaks as a carbon monoxide safety item
- Control board and harness condition evaluated before major work is quoted
- Storage and run interval guidance provided so the failure does not repeat
Our Process
- 1
History and Symptom Review
Run hours, last service, storage practice and how the failure presents all recorded.
- 2
Start and Load Test
Unit started and, where it runs, loaded to rated output with voltage and frequency monitored.
- 3
Fuel System Inspection
Carburetor or injection system, fuel lines, filters and tank condition assessed.
- 4
Mechanical Assessment
Compression measured, cooling path cleared, exhaust inspected for leaks.
- 5
Electrical Check
Control board, harness, start circuit and output windings tested.
- 6
Repair or Overhaul
Components serviced or replaced, or overhaul performed where compression and condition justify it.
- 7
Verification
Unit run under load through a sustained test before the vehicle is released.
Frequently Asked Questions
Why will my RV generator not start after sitting all winter?
Almost always fuel varnish in the carburetor. Gasoline degrades in storage, the light fractions evaporate, and what remains is a varnish that blocks the small passages in the main jet and idle circuit. The unit cranks, may fire briefly on primer, and will not run. Cleaning often works, though on units that sat for years the gaskets and diaphragms have hardened too and replacement is the better answer.
How long does generator repair take on a fifth wheel?
A fuel system service with carburetor cleaning takes one to two days. Component replacement such as a control board, starter or fuel pump takes two to four days depending on parts availability. A full overhaul takes one to three weeks. The most common delay is parts on older Onan units, where some components have been discontinued and require sourcing from rebuilders rather than the manufacturer.
What causes generator failure on RVs?
Two things dominate, and both are storage related. Fuel varnish from sitting unused blocks carburetor passages. Wet stacking from running under no load leaves unburned fuel in the exhaust and glazes the cylinder walls. The prevention for both is the same: run the generator under a real load for two hours monthly. That one habit eliminates the majority of the failures that come through our shop every spring.
Should I overhaul my generator or replace it?
It depends on compression and on the condition of everything around the engine. On a high hour unit those two options often land close enough in cost that it becomes a judgment call about the rest of the coach. We measure compression and evaluate the control board and harness condition before recommending either, because pouring an overhaul into a unit with a failing board and corroded wiring is how owners end up paying for the job twice.
Generator Repair and Service is performed in shop at OCRV Center, 23281 La Palma Ave, Yorba Linda, CA 92887, serving Long Beach, California and the surrounding region. Call (949) 799-3387 to discuss your vehicle.
Get Your Vehicle Looked At Properly
Call the shop, describe what happened, and we will tell you what the realistic scope and timeline look like. All work is performed in shop at our 35,000 square foot facility.