How often should I service my Onan Marquis Gold or Platinum generator?
Onan recommends oil and filter changes every 150 hours or annually, whichever comes first, but in Florida's humidity and Idaho's dusty conditions we service at 100 hours - both environments accelerate carb varnish buildup and air-filter restriction faster than the factory schedule accounts for. When we arrive for a service call, we drain the oil warm, swap the filter, inspect and clean or replace the air filter, check the fuel shutoff solenoid, and run the unit under load to confirm voltage output is steady at 120V before we leave.
Spark plugs go every 300 hours; at that interval we also clean the carburetor bowl and check the choke plate. Valve clearance gets inspected at 500 hours - a valve out of spec will cause hard starts and low power output that owners often misread as a carb problem. Staying on schedule matters because a generator sitting for months between uses is more likely to gum up than one serviced on time.
What does an Onan generator oil change cost on a flat rate?
$245 flat covers Onan Marquis Gold and Platinum oil and filter service: SAE 15W-40 or 5W-30 per spec, OEM oil filter, oil dump and recycle, AC and DC air-filter check, leak-down inspection, and a 30-minute load test. On-site the job runs roughly 60-90 minutes - we drain while the unit is warm so the old oil pulls cleanly, swap the filter, refill to spec, then run the generator under actual coach load (not just idle) to check output voltage and let us spot any leaks at the filter seat or drain plug before we close up.
The air-filter check matters more than most owners expect: a clogged AC filter is one of the most common reasons an Onan surges or throws a low-oil fault even when oil level is fine. If we find a filter that needs replacing, we carry common Onan sizes on the truck and quote it before adding anything to the invoice.
My generator cranks but won't start in cold weather. What is wrong?
Cold-start failures in Idaho winters usually trace to one of three causes: a battery that cranks the starter but can't sustain the voltage a spark needs to fire, a carburetor bowl coated in varnish from ethanol fuel that sat over the storage season, or a voltage regulator that's too worn to hold output under load in cold air. We start by testing cranking voltage at the battery under actual crank load - not just resting voltage, which tells you almost nothing.
If the battery passes, we pull the carb bowl and inspect for gum deposits, which typically clean up on-site with a solvent flush. If fuel delivery looks clean, we load-test the AVR. Most rigs are running again in a single visit, though a heavily varnished carb that won't clean may need a rebuild kit or replacement unit, which we carry on the truck for common generator models.
Why does my Onan run rough and surge in Florida summer?
Humid air and ethanol-blended fuel are a bad combination for Onan KY and HGJAB carburetors. The ethanol attracts moisture, breaks down during storage, and leaves a varnish residue that restricts the main jet and slow-jet - the result is the surging you hear at no-load, the hunting and stumble when the AC cycles on, and that characteristic pop on shutdown.
On-site, we pull the carb, disassemble it fully, clean the jets and passages with solvent, install new jets and gaskets, and fit a fresh fuel filter before reassembly. Most rigs run steady within a few minutes of restart. If surging continues after the rebuild, we check the choke plate and governor linkage, since worn governor springs on high-hour units can mimic a carb problem and need a separate adjustment.
Can you service Cummins RV QD diesel generators on-site?
Yes. We service Cummins QD 6, 8, and 10kW diesel generators on-site wherever the rig is parked.
The flat $265 service covers a 15W-40 diesel oil change, primary and secondary fuel filter swap, air filter inspection, coolant level and condition check, and a 30-minute load test under realistic draw to confirm the unit holds frequency and voltage without hunting or shutting down on fault codes. We carry filters for Onan-branded Cummins units on every truck, so we rarely have to order parts before showing up. If the load test surfaces a fault - common ones are low coolant temp sensor failures or fuel solenoid wear on higher-hour units - we quote that repair separately before touching anything further.
Will salt-air corrosion in coastal Florida ruin my generator case?
Salt air does more damage to a generator enclosure than most owners expect - not just surface rust, but seized fasteners, corroded exhaust shrouds, and salt creep into the AC stator windings where moisture and conductivity cause shorts or ground faults over time. When we service a coastal rig, we pull the enclosure panels, treat exposed metal surfaces with Corrosion-X, and swap any flaking or seized fasteners for stainless steel replacements so the next service isn't a fight with a drill and an extractor.
If salt has worked its way inside to the stator, we clean and inspect the windings and test output quality before buttoning it back up. In coastal Florida especially, annual service intervals matter more than the hours-based schedule in your owner's manual - salt accumulates year-round regardless of how much you run the unit. Skipping a season of preventive treatment is usually what turns a $150 service call into a stator replacement or a full enclosure swap.
What if my generator starts but won't make AC voltage to the RV?
A generator that cranks and runs but puts out no AC voltage almost always points to three places: the AVR, the brushes riding the rotor slip rings, or the capacitor on brushless units. We start by checking field voltage at the rotor and brush contact pressure before touching anything - if the brushes are worn down or the slip rings are glazed, that is a $90-$120 fix rather than a full AVR swap.
If field voltage is present but the AVR resistance values fall outside Onan spec, the AVR is the confirmed failure. AVR replacement runs $385 to $685 depending on model, and we carry the common AVRs for Marquis Gold and Platinum units on the truck, which keeps most of those same-day. If the rotor winding itself has failed, that changes the conversation - rewind cost typically exceeds the value of an older unit, so we will tell you that honestly before you spend money on parts.
Are you RVIA and RVDA certified for generator work?
Many of our techs hold RVIA and RVDA certifications, and the rest bring years of hands-on RV repair experience. For generator work specifically, that means we arrive knowing the difference between an Onan RV QG diagnostic sequence and a Cummins commercial unit - they don't troubleshoot the same way, and treating them identically is how misdiagnoses happen.
On every generator job we document the serial number and record parts in your name, which matters when you need to file a manufacturer warranty claim down the road. Our own labor and workmanship carries a 90-day warranty, and because we use OEM-equivalent parts with full documentation, manufacturer parts warranties - typically one to two years - stay intact. If a repair turns out to need dealer-level firmware or a proprietary diagnostic tool we don't carry, we tell you upfront rather than guessing.
Can you reach my RV in our covered metros if the generator dies on the road?
For emergency generator failures in our our covered metros service areas, we target a 2-4 hour response for most calls - getting to you at a campground, rest stop, or roadside pull-off with the tools and parts to diagnose on the spot. When we arrive, we run a quick load test and check the obvious failure points first: fuel delivery, spark or glow plugs, oil shutoff sensors, and the control board.
If you're outside our direct service areas, the nationwide certified-tech partner network connects you with a mobile generator tech who works the same way we do - on-site diagnosis, flat-rate quote before any work starts. Either way, confirm your location and generator make and model when you call so we can check parts availability before dispatch.
