Top 10 Most Common Generator Repair Questions Answered

1. Why won’t my generator start?

A generator that won’t start is one of the most common issues. First, check the basics:

• Is there enough fresh fuel in the tank?
• Is the fuel valve turned ON?
• Is the choke set correctly for a cold start?
• Is the on/off switch in the RUN/ON position?

Next, inspect the spark plug for fouling or damage and clean/replace if needed. Also check the air filter; a clogged filter can prevent proper starting. If your generator has a low‑oil sensor, verify the oil level is correct.

Call a professional if:

• You smell strong fuel but it still won’t start
• You’ve confirmed fuel, spark, and air, but no response
• There are clicking sounds or electrical burning smells

2. Why does my generator start then quickly shut off?

When a generator starts and then stalls after a few seconds or minutes, it’s often a fuel or safety sensor issue. First, check for:

• Low oil level triggering the low‑oil shutdown
• Old or contaminated fuel causing poor combustion
• A partially clogged carburetor or fuel filter
• Overloaded circuits right after startup

Try running the generator with all loads disconnected, then add devices one at a time. Make sure it’s on a level surface, as some low‑oil sensors are sensitive to tilt.

Call a pro if:

• It shuts down with a full tank and proper oil level
• You suspect carburetor cleaning or fuel system flushing is needed
• The engine runs rough, backfires, or emits excessive smoke

3. Why is my generator not producing any power? ⚡

If the engine runs but there’s no electricity, the problem is usually in the alternator or outlets, not the engine. First, ensure:

• The circuit breaker on the generator is switched ON
• Your extension cords or transfer switch are not damaged
• You’re plugging into the correct outlets (some are switched)

If there’s still no output, the voltage regulator, brushes, or windings may be at fault. Sometimes generators that sit unused lose their magnetic field and need “re-excitation,” a procedure best left to pros.

Call a professional electrician or generator tech if:

• The breaker instantly trips
• You notice burning smells or melted plastic
• You suspect internal alternator damage

4. Why is my generator surging or running rough?

Engine surging (revving up and down) usually points to a fuel or air issue. Common causes include:

• Dirty carburetor jets restricting fuel flow
• Old gasoline (more than 30–60 days without stabilizer)
• Clogged air filter, limiting airflow
• Incorrectly set or sticky governor linkage

Basic troubleshooting:

1. Replace old fuel with fresh, stabilized fuel.
2. Check and clean/replace the air filter.
3. Inspect the spark plug for wear or deposits.

Call a pro if surging persists or you’re uncomfortable cleaning a carburetor. Continuous surging under load can damage connected electronics and shorten engine life.

5. Why does my generator keep tripping the breaker?

A generator breaker that keeps tripping is a safety signal that something is wrong. The most common cause is overloading—running more watts than the unit is rated for. Calculate the wattage of each device and compare it to your generator’s running and surge watt ratings.

Other possible issues:

• Shorted or damaged extension cords
• Faulty appliances drawing excessive current
• Internal shorts in the generator’s outlets or wiring

Troubleshoot by:

1. Turning the generator off.
2. Disconnecting all loads.
3. Resetting the breaker and adding one device at a time.

Call a professional if the breaker trips with nothing plugged in, or if you see sparks, smell burning, or hear popping sounds.

6. Why is my generator so loud or making strange noises? 🔊

Generators are naturally noisy, but new or unusual sounds can indicate problems. Listen for:

• Knocking or banging: possibly low oil or internal engine wear
• Metallic scraping: loose parts or contact with the flywheel
• High-pitched squealing: belt, bearing, or alternator issue
• Rattling: loose bolts, handles, or frame components

Start by checking for loose screws, shrouds, or panels and tightening them. Confirm the generator is on a solid, level surface; vibration can amplify noise.

Turn the generator off immediately and call a pro if:

• Knocking continues after checking oil
• You hear grinding, scraping, or smell burning
• The unit vibrates excessively or “walks” on the ground

7. Why is my generator leaking gas or oil?

Any fuel or oil leak is a safety hazard and should be addressed quickly. Common sources include:

• Cracked or brittle fuel lines
• Loose or damaged fuel tank cap or gasket
• Worn carburetor seals or stuck float
• Overfilled oil reservoir or loose drain plug

For minor oil seepage, tighten the oil drain plug and check the oil filter (if equipped). For fuel, inspect hoses and connections; replace any that are cracked or wet. Always work in a well‑ventilated, non‑spark area.

Stop using the generator and call a professional if:

• You can’t quickly identify the leak source
• Fuel is dripping from the carburetor or tank seams
• There’s a strong fuel smell even when off

8. Why does my generator smell like gas or exhaust?

A fuel smell with no visible leak may come from:

• A slightly open fuel cap or vent
• A carburetor that’s flooded from repeated starting attempts
• Fuel splashed during refueling

Allow time for vapors to dissipate and ensure the generator is cool before refueling. Never run a generator in a garage, basement, or enclosed porch—even with doors or windows open.

A strong exhaust smell indoors is a sign of dangerous carbon monoxide (CO) buildup. Move the generator at least 20 feet away from doors, windows, and vents, and install CO detectors inside your home.

Call a pro for persistent fuel odor, suspected exhaust leaks, or if your unit fails local emissions/safety checks.

9. How often should I service my generator to avoid repairs?

Regular preventive maintenance dramatically reduces repair costs and failure risk. General guidelines (always check your manual):

• Oil change: every 25–50 hours for portables, or annually
• Air filter: inspect every 25 hours; replace as needed
• Spark plug: inspect annually; replace every 100 hours or 1–2 years
• Fuel: use fresh fuel; add stabilizer if storing more than 30 days

Standby (whole‑house) generators should have professional service at least once a year, including load testing and electrical checks.

Call a professional for:

• Annual standby generator tune‑ups
• Complex tasks like valve adjustments or governor setup
• Any service that requires opening alternator or control panels

10. Can I repair my generator myself, or do I need a professional? 🛠️

Many basic tasks are safe for handy homeowners:

• Changing oil and air filters
• Replacing spark plugs
• Draining old fuel and adding stabilizer
• Tightening loose bolts and checking cords

However, anything involving internal engine work, alternator components, voltage regulators, or control boards should be left to a licensed technician or electrician. Working inside these systems without proper training can cause shock, fire, or serious damage to the generator and your home.

You should definitely call a professional if:

• You see exposed wiring or burnt components
• The unit is under warranty (DIY work may void it)
• You’re uncomfortable or unsure at any step

Helpful Tips for Keeping Your Generator Running Smoothly

1. Run it monthly under load for 10–20 minutes to keep fuel flowing, lubricate parts, and maintain the alternator’s magnetic field.
2. Use fuel stabilizer and rotate fuel stock so gasoline never sits more than 60–90 days. For long-term storage, drain the carburetor.
3. Store and operate on a level, clean surface to prevent oil sensor issues and reduce dust intake.
4. Keep it dry and sheltered, but never indoors—use a proper generator tent or canopy rated for outdoor use.
5. Label your home circuits and typical loads so you don’t overload the generator during an outage.
6. Follow the manufacturer’s maintenance schedule and keep a log of hours, services, and any repairs for easier troubleshooting later.