Mobile RV Generator Repair in Austin & Central Texas
An onboard RV generator that won't start, surges under load, or drops off with no output is more than an inconvenience — in Texas heat, it means no air conditioning, no microwave, and no reliable power off-grid. Boss Bull Mobile RV Services diagnoses and repairs coach-mounted RV generators across Central Texas, coming to your campsite, RV park, storage facility, or driveway to restore power without requiring you to tow the coach to a shop.
Every repair, no questions asked.
Better Business Bureau accredited.
$500–$25,000. 0–35.9% APR based on creditworthiness.
Austin and Central Texas.
Overview
Central Texas heat drives RV owners to run their onboard generators hard during spring and fall camping seasons. A Cummins Onan or RVMP genset that sits unused over winter and is then called on to power a 15,000 BTU rooftop air conditioner on a 95-degree April afternoon faces two compounding challenges: the engine may have varnished fuel passageways from stale fuel, and the load is immediately at or near the unit's rated capacity. The three most common complaints we receive — won't start, surges under load, and no AC output — all trace back to this combination of deferred maintenance and high demand.
Unlike portable suitcase generators, coach-mounted onboard gensets integrate directly with the RV's transfer switch, fuel supply, and electrical distribution panel. Diagnosis requires access to the genset compartment, control board fault codes, and the ability to load-test the unit at the RV's location. Pulling the coach to a shop for a generator complaint that can be diagnosed and repaired on site is unnecessary in most cases.
Routine generator service — oil and filter change, air filter replacement, spark plug replacement, and fuel system inspection — is the single most effective way to prevent the majority of won't-start and surging complaints. Onan and Cummins recommend service intervals based on hours of use, not calendar time. An onboard genset that runs 100 hours per season reaches its first oil change interval in a single camping season; a genset that runs only a few hours per year may not hit that interval for several years but can still develop stale fuel and varnish issues from long periods of inactivity.
Boss Bull services onboard RV generators — Onan/Cummins Onan, Cummins, and RVMP coach-mounted units. We do not repair portable suitcase generators (Honda EU, Predator, Champion, or similar units). All generator service and repair is performed at the owner's location across Austin, Georgetown, Round Rock, Hutto, Cedar Park, Kyle, Buda, San Marcos, and surrounding Central Texas communities.
Onan QG series onboard generator documented in the open compartment before a service visit begins. The engine, exhaust outlet, fuel lines, and wiring are reviewed during the initial assessment.
The compartment door is opened and the unit is inspected in its installed position before any repair work begins. Fault codes are read from the control panel and the oil level, air filter condition, and fuel supply are checked as part of the initial assessment.
Common Problems We Fix
- Generator won't start — no crank or cranks but does not fire
- Generator starts then dies within seconds or minutes
- Engine surging or hunting RPM under load or at idle
- No AC output — generator runs but coach has no 120V power
- Low or fluctuating output voltage — appliances behave erratically
- Hard starting — extended cranking before the engine catches
- Excessive smoke from the exhaust — white, black, or blue
- Error or fault codes on the genset control panel
- Spark arrestor fouled or exhaust obstruction
- Fuel delivery problem — runs on choke only or stalls lean
- Overdue routine service — oil, filters, or spark plugs
Carburetor removed from an Onan QG series generator for cleaning during a service call. Varnished passageways from stale fuel are documented before the carb kit is installed.
The carburetor is removed, disassembled, and the main jet, pilot circuit, and fuel inlet seat are inspected and cleaned before the carb kit components are installed. The unit is run under load after reassembly to confirm stable operation.
Common Findings During RV Generator Repair Service Calls
Onboard RV generator service calls most often involve fuel delivery, ignition, and output issues compounded by deferred maintenance. The following conditions are documented most frequently during generator service visits across Central Texas.
- Varnished carburetor passageways — stale fuel deposits block the main jet, pilot circuit, and fuel inlet needle, causing lean running, surging, or complete no-start; the most common single finding on gasoline gensets that have sat inactive for more than one season
- Clogged fuel filters — in-line filter and primary supply filter fouled with sediment or water, restricting fuel flow enough to cause surging under load or stall when the AC compressor starts
- Fouled or oil-fouled spark plugs — carbon deposits or oil on the electrode gap produce a weak spark; the engine starts and idles but misses under the increased load of the air conditioner
- Genset start battery below cranking threshold — slow cranking that does not fire the engine, often accompanied by corroded cable terminals that reduce available cranking current further
- Onan QG series fault code lockout — unit will not restart after an overload, low-oil, or high-temperature event until the fault is acknowledged and the underlying condition is resolved
- Worn Onan slip rings and brushes — AC output absent or intermittent with the engine running; the mechanical side of the genset is functional but the rotor brushes are not maintaining contact with the slip rings
- Overdue oil service — oil significantly past change interval triggering low-oil sensor or low-oil shutdown; the sensor activates the low-oil shutdown before the engine reaches normal temperature on the first start of the day
- Air filter blockage — restricted combustion air producing rich running, black smoke, and power loss under load; common on units stored in dusty or high-pollen environments without the compartment door fully closed
Technician Observations
What Owners Commonly Report
Presenting complaints we hear most often on these service calls.
- Generator ran fine last season but now cranks without starting
- Starts up but dies within 30 seconds, sometimes after a few minutes
- Generator runs but there is no power to any outlets in the coach
- Engine surges and hunts constantly — speed goes up and down at idle and under load
- Generator starts and runs but the air conditioner trips a breaker when it tries to come on
What We Frequently Find
Actual conditions we document when we arrive on site.
- Varnished carburetor jets and fuel passageways from stale fuel — the single most common root cause of no-start and dies-after-starting complaints on gasoline gensets that sat for one or more seasons without fuel stabilizer or a carburetor drain
- Clogged fuel filters — both the in-line filter at the genset and the primary filter upstream in the fuel supply can accumulate debris and water over time, restricting flow enough to cause lean-running, surging, or stall-on-load behavior
- Fouled spark plugs — carbon-fouled plugs from rich running or oil consumption produce a weak spark that cannot maintain combustion under load; the engine starts and idles but bogs and dies when the AC compressor kicks in
- Weak or failing genset start batteries with corroded terminals — an onboard genset draws significant cranking current from the house battery bank or a dedicated start battery; a battery below threshold cranks slowly and fails to start the engine even when the engine itself is mechanically sound
- Control board faults and fault code lockouts — Onan QG series units log fault codes that can prevent restart after a low-oil, high-temperature, or overload event; clearing the fault and addressing the root condition is required before the unit will start again
- Slip ring and brush wear on older Onan units — worn brushes produce intermittent or complete loss of AC output with the engine running normally; the generator runs and sounds correct but delivers no power to the transfer switch
- Overdue oil changes — onboard generators that have significantly exceeded their service interval develop oil that has lost viscosity, triggering the low-oil shutdown sensor before the engine reaches operating temperature
Service Recommendations
What we typically advise based on our findings.
- Exercise the onboard generator under load for at least 30 minutes every 30 days — short no-load runs do not circulate oil through the system or keep fuel passageways clear; 30 minutes at 50% or greater load keeps the carburetor, fuel lines, and oil system in working condition between camping seasons
- Add fuel stabilizer to the tank at the end of each camping season and run the generator for 10–15 minutes under light load to circulate stabilizer through the carburetor — untreated gasoline begins to varnish in as little as 30 days in Texas heat
- Schedule annual generator service — oil, oil filter, air filter, and spark plugs — regardless of whether the unit is showing problems; most won't-start complaints on a well-maintained genset trace to a spark plug or air filter, not a major mechanical failure
- Keep the generator load within its rated capacity — running a 4,000-watt Onan QG 4000 at sustained loads above 3,600 watts causes the voltage regulator and engine to run at the edge of their operating range, accelerating wear and producing voltage instability
- Document the hour meter reading at each service visit — Onan and Cummins service intervals are hours-based; knowing the current hours allows the technician to identify what services are due and which are upcoming
Why RV Owners Choose Mobile RV Service
- On-site diagnosis using genset fault codes and load-testing at the coach — no need to pull the RV to a shop for a generator complaint that can be resolved where it sits
- No towing required — Boss Bull comes to your campground, RV park, storage facility, or home
- Common generator parts — filters, spark plugs, carb kits, brushes — stocked on the service van for same-visit repairs
- Load-testing completed under real-world AC and appliance load at the owner's location — not on a shop floor at no load
- Service across Central Texas: Austin, Georgetown, Round Rock, Hutto, Cedar Park, Leander, Kyle, Buda, San Marcos, and surrounding areas
- Wisetack financing available for larger generator repairs or replacement
Onboard RV Generator Brands & Systems We Commonly Service
- Onan / Cummins Onan — RV QG series gas and diesel onboard gensets (QG 2800, QG 4000, QG 5500, QD 3200, QD 5000)
- Cummins coach-mounted generator units
- RVMP onboard RV generators
- Onboard gasoline generators — carb service, fuel system, spark plugs, oil service, and electrical output
- Onboard diesel generators — oil service, fuel filter, injector check, and control board diagnostics
- Onboard LP (propane) generators — LP pressure, regulator, and fuel delivery service
- Genset control boards — fault code diagnosis, reset, and board replacement
- Transfer switch interface — load-testing and transfer switch operation verification
Generator run-tested under load at the owner's location following a service visit. Output voltage and frequency are confirmed stable before the compartment door is closed.
Every generator service and repair visit is concluded with a load test at the coach — AC on, slides extended, appliances running — to confirm stable voltage output and engine RPM under the real-world load the owner will place on the unit.
Related Services
Service Areas
Frequently Asked Questions
What Our Customers Say
“Our camper AC went out and we called Rich on a Saturday, thinking no way we were going to get someone out on the weekend. But Rich came out that afternoon, took a look at the unit and came up with a solution.”
“He went into great detail telling me what was wrong (even showed me) and what would need to be done. He is very responsive, respectful and efficient!”
“Prices are fair. They communicate well. They show up on time. They do what they say they will do. I will never use someone else.”
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