Whole-Home Generator Maintenance Checklist

A standby generator is a lot like a fire extinguisher: the only time you truly need it is when you can't afford for it to fail. But unlike an extinguisher, a generator has moving parts, an engine, oil, fuel, and a battery — all of which need attention on a schedule. Walk through these checks with us and keep that backup power actually backed up.

1. Run It Monthly — Under Load

The single most important thing you can do is exercise your generator. An engine that sits for weeks at a time collects moisture, forms sticky varnish in the carburetor, and lets the battery drain. Follow your owner's manual, but the general rule is once a month, run it for 20 to 30 minutes under at least half load — meaning turn on circuit breakers, run the AC or the well pump, and let it really work.

• Run it with real load. Idling isn't enough. Load the unit so the engine warms to operating temperature and burns moisture out of the oil and exhaust.
• Let it exercise. Monthly runs also keep the electronic transfer switch and the generator's control board exercised and working.
• Listen and look. Any surging, smoke, or strange noises during the test run are early warning signs worth fixing before a storm.

If you can't run your unit yourself — many homeowners are understandably uncomfortable starting a big standby rig — this is exactly the kind of service we handle for you at the shop.

2. Oil, Filter & Spark Plug on Schedule

A standby generator uses its engine oil every time it runs, and oil breaks down faster than most owners expect. The maintenance intervals below are typical, but always defer to your specific make and model:

• Oil change. Most air-cooled home generators recommend an oil change after the first 25 hours and then every 100 hours or once a year — whichever comes first. Change it before winter, not after.
• Oil filter. Replace it with every oil change on units that have one. A clogged filter starves the engine of lubrication under load.
• Spark plug. Inspect and replace the plug annually or per the hour schedule. A fouled plug is a common reason a generator cranks but refuses to fire.
• Air filter. A dirty air filter chokes the engine and hurts fuel economy. Clean or replace it seasonally — more often if your unit sits in Kentucky dust.

If you've been meaning to keep up with oil changes and simply haven't, you're not alone — it's one of the most common catch-up jobs we do, and it's quick once someone with the right tools gets to it.

3. Battery: Keep It Charged and Connected

Most whole-home generators are connected to a small battery that starts the engine automatically during an outage. That's the very moment you need it — and the most common reason generators fail when called upon is a dead battery.

• Test voltage and charge. The battery should sit at roughly 12.4 volts or higher when the unit is off. A battery that won't hold a charge needs replacement.
• Keep the charger working. Standby units have a trickle charger that keeps the battery topped up. Make sure it's plugged in and functioning — a dead charger is a dead battery in waiting.
• Clean the terminals. Corrosion between the cable and the post reads like a dead battery even when the battery is fine. A wire brush and a clean, snug connection fix it.
• Replace on age. Standby batteries typically last two to four seasons. Older than that, replace it proactively before a storm, not during one.

4. Fuel: Stabilized, Fresh, and Full

Ethanol-blended gasoline breaks down within a couple of months, absorbs moisture, and leaves varnish behind in the carburetor and fuel lines. For a generator that might sit for weeks between outages, fuel management is critical:

• Use fuel stabilizer. Add a quality stabilizer to every fill so the gas stays fresh between monthly runs. It's cheap insurance.
• Rotate your fuel. Don't leave the same gas in the tank for months. Use stabilized fuel within the recommended window and refill with fresh gas.
• Keep the tank full. A full tank leaves less room for condensation and water to collect. Fill it before storm season.
• Drain if it sits long. If a generator isn't going to run for several months, drain the carburetor and tank to prevent varnish.

5. Exhaust & Carbon Monoxide Safety

Carbon monoxide kills silently, and generators are involved in too many home CO tragedies every winter. Make these checks a habit:

• Inspect the exhaust. Look for rust, leaks, blockages, or anything that could restrict exhaust flow on the muffler and discharge piping.
• Check CO detectors. Make sure you have working carbon monoxide detectors near sleeping areas and test them whenever you service the generator.
• Never run it indoors. This includes garages, basements, and even carports. Keep generators at least several feet away from windows, doors, and vents.

6. Transfer Switch: Test the Auto-Start Path

On an automatic standby system, the transfer switch is what senses the power outage, signals the generator to start, and safely disconnects your home from the grid. If the switch is stuck or the controls have drift, your generator may be healthy but absolutely useless when the power goes out. Test the full automatic transfer — kill the main breaker, let the generator pick up the load, then restore power and confirm it switches back cleanly. If any part of that sequence glitches, get it looked at before you need it.

Maintenance Schedule at a Glance

Here's the schedule we recommend for Kentucky homeowners, from storm prep to annual service:

When to Call the Shop

Generators are not the place for guessing. Electrical work, transfer switches, and a finicky carburetor can all leave you in the dark in the middle of an ice storm — and a mistake with exhaust or fuel is genuinely dangerous. If the unit won't start, the transfer switch glitches, the battery won't hold a charge, or it's simply been a few years since a professional looked at it, that's the right time to call a pro.

Turf & Trail Small Engine Repair is based in Richmond, KY and serves Berea, Waco, Kirksville, and the surrounding Madison County area. We service generators of every major brand — Generac, Kohler, Honda, Champion, Briggs & Stratton, and more — and we diagnose before we quote. You'll get a straight answer and a firm quote before any work starts — no surprise bills.

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Generator Maintenance FAQ

How often should I run my whole-home generator?
Once a month, for about 20 to 30 minutes, and under at least half load. That keeps the battery charged, burns off moisture, and prevents the carburetor from gumming up.

How often does a generator need an oil change?
Most units call for an oil and filter change annually or about every 100 hours of run time — whichever comes first. Change it before winter storm season.

Why won't my generator start when the power goes out?
The top reasons are a dead battery, old or stale fuel, a fouled spark plug, or a transfer switch / control issue. A professional load test can pinpoint it.

Do you service and repair whole-home generators?
Yes. We service generators in Richmond and across Madison County, KY and give you a firm quote before any work begins. Call (859) 661-8877.