RV Generator Repair in Mesa

The RV generator is the component most damaged by the way rigs are used in Arizona: run hard in season, then left to sit through five months of extreme heat with fuel in it. That is why most generator trouble between October and December comes down to fuel system contamination rather than anything mechanically wrong.

What can be handled on site

Will not start: fuel, spark, compression, starter, and control diagnosis in that order.
Starts and dies: usually fuel delivery, a blocked jet, or a fuel pump that has lost prime.
Surging or hunting under load: carburetor, governor, or a partially blocked fuel path.
No AC output with the engine running: brushes, capacitor, voltage regulator, or breaker.
Runs rough, smokes, or will not take load: plugs, filters, air path, valve adjustment.
Routine service: oil and filter, air filter, plugs, fuel filter, and a load test.
Exhaust and mounting concerns, which matter more than anything else on this list for safety reasons.

Everything is done where the rig sits: resort space, storage lot, or driveway.

What it costs

Job	Typical range
Trip fee	$75–$150
Labour	$125–$190/hr, one-hour minimum
Carburetor clean or rebuild	$350–$800
Full service: oil, filters, plugs, load test	$300–$550
Fuel pump or fuel system repair	$350–$900
No-output electrical diagnosis and repair	$400–$1,200
Larger internal repairs	Quoted after diagnosis

The same approach as every other job on the pricing page: diagnosis first, then a number you approve before any work starts.

Why summer storage destroys generators here

Modern pump gasoline, particularly with ethanol content, is not a storage fluid. In a 115-degree storage lot the light fractions evaporate out of the carburetor bowl and leave behind a varnish that sets like glue in the jets and passages. Five months is more than enough. Ethanol also draws moisture, which corrodes the aluminium in a carburetor from the inside.

The three things that prevent it, in order of effectiveness:

Run it monthly under load, about two hours. Nothing else comes close. A generator that runs regularly keeps fresh fuel in the bowl and keeps everything lubricated.
Treat the fuel with a stabiliser if the rig genuinely has to sit, and run it long enough afterward to get treated fuel through the carburetor.
Shut the fuel off and run the bowl dry before long storage on units that allow it.

An owner who does the first one essentially never needs a call-out for a generator that will not start.

Heat, load, and honest expectations

Generators are rated at sea level in moderate temperatures, and they lose output as ambient temperature and elevation rise. At 110 degrees in the East Valley a unit is not going to make its nameplate rating. If your generator has always struggled to carry two rooftop air conditioners on a July afternoon, that may be arithmetic rather than a fault, and a rebuild will not change it.

Related: starting two ACs simultaneously is what trips generators. Staggering them, or fitting soft-start devices on the air conditioners, solves a great many “my generator cannot handle my rig” complaints for less than any generator repair.

The safety part

Two things to raise on any generator visit, whether or not they came up:

Exhaust. A generator exhaust leak or a corroded tailpipe on a motorhome is a carbon monoxide risk, and RV generator exhaust systems live in a harsh environment. If one turns up, we tell you, and our recommendation is not to run it until it is dealt with.

CO alarms. Check that yours works and is within its service life. They expire. This is free advice and it is the most important sentence on this page.

Service area

On site across Mesa, Apache Junction, Gilbert, Tempe, Chandler, Queen Creek, Gold Canyon, and Casa Grande. The Onan generator page covers the failure patterns on the units in most motorhomes, and the repair cost calculator gives you a range before you call.

Frequently Asked Questions

My generator will not start after sitting all summer. What is it?

Usually fuel. Gasoline left in a carburetor through a Phoenix summer varnishes and blocks the jets, and stale fuel is the most common reason an RV generator will not start or surges under load. A carburetor clean or rebuild is the usual fix, and it is far cheaper than people expect.

What does RV generator repair cost?

Carburetor service, fuel system work, plugs, filters, and starting faults typically run $300–$900 including the trip fee and labour. Rebuilds and control board or stator faults go higher, and diagnosis has to come before the quote, because a generator that will not start is usually cheap and occasionally is not.

Do you service Onan generators?

Yes, along with the other common RV and portable units. Onan is what is mounted in most motorhomes and many fifth wheels, and the failure patterns on them are well understood. We are independent, not a dealer or a warranty station, which is the point of mobile service.

How often should a generator be run?

Under load, for about two hours, once a month. That is the manufacturer's own advice and it is the single most effective thing an owner can do. Generators do not fail from use in this climate, they fail from sitting, and the storage months are what kill them.