RV Generator Repair in Guntersville, Alabama
When you're off-grid, your generator is your power source for everything. When it won't start, runs rough, or shuts down under load, your trip stops with it. We diagnose and repair RV generators right.
No Power Off-Grid Means No AC, No Comfort, No Trip
Your RV generator is one of the most neglected components on the rig — until it fails. Most owners run it occasionally, don't follow the service schedule, and store it for months at a time with fuel sitting in the carburetor. Then they need it and it won't start.
RV generators are small engines with electrical generating equipment attached. They fail in predictable ways: fuel system problems from sitting, carburetor issues, oil-related shutoffs, and electrical faults in the output side. The diagnosis path is methodical — fuel, spark, compression, output — and it leads to a specific component failure, not a parts swap hoping something works.
We service and repair built-in RV generators. If your generator isn't producing reliable power, call us and describe what it's doing. We can usually tell you the likely cause before you bring the rig in.
Generator Problems We Diagnose and Fix
Most generator failures fall into a handful of categories. Here's what we see most often and what causes them.
Won't start at all
The most common cause is fuel delivery. Check that your main fuel shutoff is open, that you have at least a quarter tank of fuel (most generators won't draw from the bottom quarter), and that the fuel hasn't been sitting for months. A clogged carburetor from stale fuel is the single most common generator repair we do. The engine cranks but won't fire because the jets are varnished shut.
Starts then shuts off
A generator that runs for a few minutes then stops is usually triggering a safety shutoff. The most common causes are low oil pressure (the oil level is low or the oil pressure sender has failed), overheating from a blocked air intake, or an overload — too much electrical demand for the generator's rated output. We test oil pressure, temperature, and electrical load to identify which protection tripped.
Runs rough or surges
A generator that hunts or surges at idle — RPMs rising and falling rhythmically — has a fuel delivery problem. The carburetor is not maintaining a consistent air/fuel mixture, usually because of a partially clogged jet or a failing needle valve. Running rough under load points to either a fuel issue or a problem on the electrical output side such as a failing voltage regulator.
Won't start the AC under load
Air conditioners draw two to three times their running wattage on startup. A generator that runs fine at idle but can't start the AC is either undersized for the load, producing low voltage from a failing AVR, or already carrying too much load from other appliances. We test output voltage and frequency under load to determine if the generator is performing to its rated capacity.
Hard to start — cranks but won't fire
Beyond fuel, hard starting can indicate a choke that isn't closing on cold starts, a weak spark from a fouled or worn spark plug, or low compression from engine wear. On Onan generators, the choke solenoid is a known failure point — if it fails, the choke doesn't close and cold starts become nearly impossible. Spark plugs on generators that sit are often the cheapest fix we find.
Produces power but trips breakers
If the generator runs and produces voltage but keeps tripping the RV's main breaker or its own breaker, the output frequency or voltage is out of spec — usually from a failing AVR (automatic voltage regulator) or a load that exceeds the generator's rating. We test output with a meter under actual load conditions to confirm what the generator is producing before recommending parts.
The Most Preventable Generator Repair Is the One You're Probably Facing
The number one generator repair we perform is carburetor cleaning from sitting with stale fuel. It's entirely preventable. Here's what you need to know to keep your generator running when you need it.
What Onan Recommends
Service every 150 hours or annually, whichever comes first.
Oil and filter change at each service interval.
Air filter inspection and replacement as needed.
Spark plug inspection or replacement.
Run the generator under at least 50% load for two hours per month to exercise it and burn off moisture.
What We See in the Shop
Generators that sat all winter with fuel in the carburetor and won't start in spring.
Oil that hasn't been changed in years, causing internal wear and oil pressure faults.
Air filters so clogged the engine can't breathe properly.
Spark plugs original to the RV with 10+ years of use.
If your generator hasn't been serviced in over a year, a full service is the right starting point before diagnosing any other issue. A clean, well-oiled engine with fresh plugs solves most problems without further diagnosis.
Why RV Owners Trust Us With Their Generator
National Champion of RV Techs®
Our founder is the 2-time RVIA Top Tech and co-creator of the RVTI certification program. Generator diagnosis is part of the complete RV system knowledge our technicians carry.
Fuel, Spark, Compression, Output
We test the full sequence. Not just the obvious symptom — the complete chain from fuel delivery through electrical output. That's how you find the actual problem instead of replacing parts that weren't the cause.
Service Parts in Stock
We stock common service parts for Onan generators — oil filters, air filters, spark plugs, and carburetors for the most common models. Most generator services are completed the same visit.
RV Generator Questions We Hear Every Day
The most common cause of a no-start generator is a fuel delivery problem — either the fuel shutoff valve is closed, the generator ran out of fuel (most generators won't run on the last quarter tank by design), or a clogged carburetor is preventing fuel from reaching the engine. Other causes include a dead starting battery separate from the house bank, a choke that isn't opening properly on cold starts, or a failed fuel pump. If the generator cranks but won't fire, the fuel system is almost always the starting point for diagnosis.
A generator that starts and runs briefly then shuts off is usually protecting itself. The most common causes are low oil triggering the oil pressure shutoff, overheating from a blocked air intake or failed cooling system, an overloaded circuit drawing more power than the generator is rated for, or a fault in the automatic voltage regulator. Some generators also have a low fuel cutoff that activates before the tank is actually empty. We test oil pressure, temperature, electrical output, and load to determine which protection circuit triggered the shutdown.
An air conditioner requires a surge of power on startup that can be two to three times its running wattage. If the generator is undersized for the AC, or if other appliances are already drawing power, the generator may not have enough capacity to start the AC compressor. A generator that is running rough or producing low voltage will also fail to start the AC even if it's rated for the load. We test the generator's actual output voltage and frequency under load to determine if the problem is the generator, the AC, or a sizing mismatch.
Onan and Cummins recommend service every 150 hours of operation or annually, whichever comes first. Service includes an oil and filter change, air filter replacement, spark plug inspection or replacement, and fuel filter service. Generators that sit unused for extended periods need carburetor attention — fuel degrades and varnishes the jets, causing hard starts and rough running. If your generator hasn't run in over a year, a full service and carburetor cleaning is the right starting point before diagnosing anything else.
We service Onan (Cummins Onan), which is the most common brand found in factory-installed RV generators, as well as other built-in and portable generator brands. If you have a generator in your RV that isn't starting, running properly, or producing the power you need, call us with the brand and model and we can tell you how we can help.
RV Generator Repair Near You in North Alabama
Our shop is at 3619 AL-69 in Guntersville, Alabama. RV owners bring their generator problems to us from across North Alabama.
Serving Guntersville, Albertville, Boaz, Arab, Scottsboro, Fort Payne, Cullman, Attalla, Gadsden, Oneonta, Decatur, Huntsville, Grant, New Hope, Owens Cross Roads, Hampton Cove, Madison, and Athens.
Tell Us What Your Generator Is Doing
Won't start, shuts off, runs rough, or won't carry the AC — describe the symptom and we'll tell you what's likely wrong before you drive in.