Types of RV Generators

Before getting into maintenance, it helps to know what type of generator you actually have, since that determines both the fuel you are working with and where to look for service specifications.

Built-in RV generators typically run on gasoline, propane or diesel, and the fuel type is usually tied to the RV's own fuel system on motorized units. These built-in units are generally installed in a dedicated compartment with its own venting, and many motorized RVs wire the generator through an automatic transfer switch that shifts the coach's electrical load between shore power and generator power without you needing to flip anything manually. Portable generators are the common alternative for towable RVs or as backup for a built-in unit, and they are typically gas or propane powered, with some dual-fuel models able to run on either; because they sit outside the RV rather than in a vented compartment, placement and distance from windows and vents becomes something you actively manage every time you use one, which the safety section below covers. Whichever type you have, the single most useful document you can locate is your generator's own operator's manual, since service intervals below vary meaningfully by model and specification, and the manual is the authoritative source for your specific unit.

Routine Maintenance Rhythm

Generator maintenance follows a rhythm similar to a small engine or car, just on a different schedule, and the numbers below should be treated as typical starting points rather than fixed rules for every model.

Oil changes. Most manufacturers call for an earlier first oil change than the ongoing interval, since a new engine sheds more metal particulate as it breaks in. Expect that first change to land sooner than later ones, commonly cited in the neighborhood of 20 hours of run time or the first year, whichever comes first. After that, ongoing oil and filter changes are commonly cited around every 150 hours of run time or annually, though some model years and specifications cite figures as low as 50 hours, so confirm the exact number for your specific model in its manual rather than assuming one interval fits every generator.

Air filter. A commonly cited interval is every 500 hours or once a year, more often if you run the generator in dusty conditions. A dirty air filter restricts airflow to the engine and can show up later as reduced output or a rough-running generator, so it is worth checking more often than the calendar interval if you have been camping somewhere dusty.

Spark plugs (gasoline models). A commonly cited replacement interval is roughly every 450 hours of run time.

Spark arrestor and fuel filter. Spark arrestors are commonly serviced around once a year or every 150 hours, and fuel filters around every 500 hours or every two years.

Coolant (liquid-cooled diesel models). On diesel units with a coolant system, intervals in the range of every 1,000 hours or two years are commonly cited, extending to as long as four years with a long-life coolant, though this is specific to certain diesel model lines and should not be generalized to gas or propane units.

Across every interval above, treat the hour and year figures as ranges rather than pinned numbers, and check the maintenance schedule printed in your own generator's operator manual for the figure that actually applies to your unit. If your RV came with the generator's manual, keep a copy somewhere accessible, such as a document folder in your tow vehicle or a photo on your phone, so the correct interval is on hand the first time a warning light or a seasonal reminder tells you service is due.

Why Monthly Exercise Matters

If there is one habit that prevents more generator problems than any single maintenance task, it is running the unit regularly even when you are not actively using it.

Follow your generator manual's exercise schedule, including how often, how long and at what load to run it. The point is to let the engine reach operating temperature under load rather than starting it briefly; running an air conditioner or other appliances is an easy way to add load.

This monthly exercise routine relubricates internal engine components and drives off moisture that accumulates inside the engine and generator housing. It also burns off stale fuel and the varnish that forms from it and helps keep electrical contacts clean. Skipping this for a season, particularly over a winter storage period, is one of the most common reasons an RV generator refuses to start cleanly the next time it is needed. If you are storing the RV for the off-season, pair this habit with the rest of your winterization routine; our RV winterization guide and spring dewinterization guide both cover the surrounding steps.

Troubleshooting: Generator Surging

A generator that surges, meaning the engine speed rises and falls in an uneven rhythm rather than holding steady, is one of the more common complaints, and the most frequent cause is fuel-related rather than a serious mechanical failure.

The leading cause is a carburetor gummed up with varnish left behind by stale ethanol-blended gasoline sitting during storage; this can start forming in as little as about a month of sitting unused, which is another reason the monthly exercise habit above matters. An improperly adjusted governor is a related cause worth checking if fuel quality is not the culprit. Vacuum leaks, from a cracked hose or a worn gasket, are a secondary but real possibility as well.

If your generator has been sitting for more than a month or two with fuel in the tank, and it starts but runs unevenly, stale fuel and a gummed carburetor are the first thing to rule out, either by having a technician clean the carburetor or by running a fuel stabilizer and exercising the unit going forward.

Troubleshooting: No-Start and Low-Output Symptoms

Not every generator problem is fuel-related. Splitting symptoms into no-start and low-output/overload categories makes it easier to narrow down a cause before calling a technician.

No-start. Common causes include a dead or weak start battery, a tripped circuit breaker, a low-oil shutdown safety switch that has kicked in, a clogged fuel filter or stale fuel in the line, and, on gasoline models, a bad spark plug. Work through these roughly in order, starting with the battery, since it is the easiest to check and the most common culprit.

Low output or nuisance overload trips. Common causes include an overloaded circuit that is simply asking more of the generator than its rated capacity, a dirty air filter restricting airflow, and worn brushes or a failing voltage regulator on the generator end itself rather than the engine.

A note on diagnosis: some generators display error indicators, but the specific meaning of any numeric code varies by model and manufacturer, and there is no single universal code table across RV generators. Rather than guessing at what a flashing light or code number means, check your unit's own manual or contact the manufacturer or a qualified technician for the code definitions specific to your model.

Working through symptoms in this order also saves money. A weak battery or a tripped breaker takes a few minutes and no parts to rule out, while a carburetor rebuild or a voltage regulator replacement takes real time and cost. Confirming the simple causes first, before assuming the generator itself has failed, is the difference between a five-minute fix and an unnecessary shop visit.

Running a Generator at Altitude

If you spend meaningful time camping at elevation, altitude is worth understanding as a generator performance factor, even though the exact numbers vary by unit.

Generators lose power as elevation rises and the air thins, and some models offer high-altitude kits. Whether you need one, and when to install or remove it, depends on the generator model, so follow the generator manufacturer's instructions or ask a dealer or qualified service center before changing any carburetor parts.

Carbon Monoxide Safety

No maintenance or troubleshooting step matters as much as running a generator safely, since carbon monoxide from generator exhaust is invisible, odorless and can be fatal in an enclosed or poorly ventilated space.

For a portable generator, the Centers for Disease Control and Prevention recommends running it outdoors only, positioned more than 20 feet away from windows, doors and vents. For a built-in generator, follow the RV and generator manuals for exhaust-system checks and safe operation. Never run either type in a garage or other enclosed space. Before operating a generator, follow the CO alarm manufacturer's testing instructions and confirm that the alarm has power and is operating. Check its replacement date and follow its manufacturer's instructions for replacement.

This is especially relevant if you rely on generator power for off-grid stays; our guide to boondocking for beginners covers the broader off-grid power picture, including alternatives worth weighing alongside generator run time.

Keeping a Maintenance Log

A simple log of run hours, oil changes, filter swaps and any exercise runs is the single easiest way to stay ahead of every interval above without memorizing a schedule, and it also becomes useful information if you ever sell the RV. A dated entry every time you service or exercise the generator turns a vague sense of "I think I changed the oil last summer" into an answer you can actually check.

A basic log does not need special software. A notebook kept in the same storage bay as the generator, a spreadsheet on your phone, or notes in a maintenance app all work, as long as you record the date, the approximate run-hour reading if your unit tracks hours, and what was done. Over a few seasons, that log also makes it much easier to notice a pattern, such as an oil change interval that keeps landing earlier than expected, which can be an early sign worth mentioning to a technician even before a more obvious symptom shows up.

Knowing When to Call a Professional

Some generator issues are within reach of an owner with basic tools and a manual on hand. Others are worth handing to a qualified technician rather than working through alone.

Bring in a qualified technician when a symptom does not resolve with the basic checks above, when diagnosis or repair involves the generator's electrical end, or when a diesel unit's coolant system needs service, since that work carries more risk of expensive mistakes than a routine oil change. A generator that trips breakers repeatedly even under a normal load, one that has been dropped or exposed to significant water, or one that produces a burning smell during operation are all situations where stopping and calling a technician is the right call rather than continuing to troubleshoot on your own.

It is also worth folding a generator check into your broader seasonal routine rather than treating it as a separate task. Our year-end RV maintenance checklist is a good place to make sure the generator gets included alongside everything else you check before and after the off-season, so it never becomes the one system you forget about until the moment you need it most.

Frequently Asked Questions

Can I run my RV generator inside a closed garage or carport for a quick test? No. Never run any generator, portable or built-in, in a garage, carport or other enclosed space, however briefly you plan to run it. Even a short test run in an enclosed or semi-enclosed space can allow carbon monoxide to build up to dangerous levels.

How long can stale fuel sit in the generator before it becomes a real problem? Ethanol-blended gasoline can begin forming carburetor-gumming varnish in as little as about a month of sitting unused, which is why the monthly exercise habit matters even during a season when you are not using the RV. If fuel has sat for a full off-season without stabilizer or exercise, plan on a carburetor inspection before assuming the generator is fine.

My generator's manual and an online forum give different maintenance intervals for the same part. Which one should I follow? Follow your unit's own operator manual and the model/spec-specific tag or plate on the generator itself. Hour intervals for oil, filters, plugs and coolant vary by model year and specification, so a number that is accurate for one generator can be wrong for another that looks similar.

Does a portable backup generator need the same monthly exercise routine as a built-in unit? Follow the manual for that generator. Stale fuel and lubrication matter for portable generators too, but the right exercise and storage routine depends on the model.