Top 10 Most Common Gas Generator Repair Questions Answered

1. Why won’t my gas generator start?

A gas generator that won’t start usually has an issue with fuel, spark, or air. Start with the basics:

1. Check fuel level and age. Old gasoline (over 30–60 days) can prevent starting. Drain and refill with fresh, stabilized fuel.
2. Inspect the on/off and fuel valve switches. Make sure both are set to ON.
3. Check the choke position. Cold start = choke ON; once it fires, slowly move to RUN.
4. Inspect the spark plug. Remove, clean, and check for cracks or heavy deposits. Replace if needed.
5. Check the air filter. A clogged filter can choke the engine. Clean or replace.

Call a professional if you smell strong fuel, hear odd noises, or the pull cord/ starter is very hard to pull.

2. Why does my generator start but then stall or shut off?

If your gas generator starts then dies, it’s usually a fuel delivery or airflow problem. Common causes include:

• Clogged carburetor from varnished old fuel
• Dirty air filter restricting airflow
• Low oil shutdown triggered by low or incorrect oil
• Overloaded generator causing the engine to bog down ⚡

If cleaning the air filter, changing fuel, and checking oil don’t help, have a technician clean or rebuild the carburetor.

3. Why is my gas generator not producing electricity?

When the engine runs but there’s no power at outlets, the problem is in the alternator or controls, not the engine.

1. Check the circuit breakers. Many generators have resettable breakers; make sure they’re ON.
2. Test multiple outlets with a known-good device (like a lamp).
3. Inspect for tripped GFCI outlets and press RESET if equipped.
4. Make sure the generator is not in “neutral” or “off-load” mode (on larger units).

If there’s still no output, do not open the alternator yourself. High voltages are dangerous—call a qualified generator technician. ⚠️

4. Why is my generator surging or running rough?

Surging (revving up and down) or rough running often points to an air/fuel mixture problem.

Common causes:

• Partially clogged carburetor jets
• Dirty or restricted air filter
• Old or contaminated fuel
• Incorrect choke position (choke partly closed when warm)

Troubleshooting steps:

1. Replace old fuel and add fuel stabilizer.
2. Clean or replace the air filter.
3. Run the generator for 15–20 minutes under moderate load to clear minor deposits.
4. If surging continues, the carburetor likely needs a full cleaning.

Call a professional if the generator:

• Backfires loudly
• Emits black smoke (running rich)
• Surges even with fresh fuel and a clean filter

These symptoms can indicate deeper carburetor or governor issues that require expertise.

5. Why does my gas generator keep tripping the breaker?

Frequent breaker trips mean your generator is protecting itself from overloads or faults.

Common reasons:

• Too many devices plugged in (exceeding watt rating)
• High startup loads from fridges, pumps, or AC units
• Short circuit or faulty cord/appliance
• Damaged outlet or internal wiring

How to troubleshoot:

1. Turn the generator off, then unplug everything.
2. Reset the breaker, restart, and plug devices in one at a time.
3. Prioritize essential loads (fridge, sump pump) and avoid high-draw tools simultaneously.
4. Replace any warm, scorched, or damaged cords immediately.

If the breaker trips even with light or no load, there may be an internal fault. Stop using the generator and call a professional to prevent fire risk. 🔥

6. Why is my generator leaking gas or oil?

Any leak on a gas generator is a serious safety concern.

Gas leaks may come from:

• Cracked or loose fuel lines
• Faulty fuel shutoff valve
• Leaking carburetor bowl gasket

Oil leaks may come from:

• Overfilled crankcase
• Loose drain plug
• Worn gaskets or seals

Never run a generator with an active fuel leak. Gas vapors + hot engine = fire/explosion risk. If tightening clamps or drain plugs doesn’t solve it, have it professionally inspected.

7. Why is my generator so loud, and can that be repaired?

Portable gas generators are naturally loud, but excessive or new noises can signal trouble.

Normal loudness comes from:

• Open-frame design
• Engine speed (typically 3,600 RPM)
• Basic mufflers

Abnormal noises to watch for:

• Metallic knocking – possible engine damage
• Grinding or squealing – bearing or alternator issues
• Rattles – loose brackets, bolts, or panels

Quick checks:

1. Tighten loose bolts, handles, and covers.
2. Place the generator on a solid, level surface with rubber pads if possible.
3. Keep it at least 20 feet away from living areas (also safer for exhaust).

If you hear knocking, grinding, or very sudden changes in sound, shut it down and call a technician. Internal engine damage gets worse quickly if ignored. 🛠️

8. Why does my generator smoke, and what do the smoke colors mean?

Exhaust smoke color is a useful diagnostic clue.

Basic troubleshooting:

• Black smoke: Clean/replace air filter, ensure choke is OFF after warm-up.
• Blue smoke: Check that oil is not overfilled and unit is level.
• Persistent thick white smoke (on air-cooled portables) is unusual—stop using and have it inspected.

If smoke is continuous, thick, or accompanied by power loss or loud knocking, shut down immediately. Running a smoking engine can cause permanent damage and is a fire risk.

9. How often should I service my gas generator, and what does that include?

Regular maintenance prevents many costly repairs and ensures reliability during outages 💡.

Typical schedule for portable gas generators (check your manual for specifics):

• Every 8–20 hours (or each day of heavy use): Check oil level, visual inspection
• Every 25–50 hours: Change engine oil (more often in dusty/hot conditions)
• Every 100 hours: Replace spark plug, clean/replace air filter
• Annually: Full inspection, fuel system check, carb cleaning if needed

Basic service includes:

• Oil and oil filter (if equipped) change
• Spark plug replacement
• Air filter service
• Fuel filter inspection
• Testing under load

If you’re not comfortable with engine work, have a professional perform annual servicing, especially before storm season.

10. When is it better to repair my generator vs. replace it?

Deciding whether to repair or replace depends on age, cost of repair, and usage needs.

Consider repair if:

• The generator is under 5–7 years old
• Repairs are less than 40–50% of the cost of a new comparable unit
• The frame, alternator, and engine block are in good condition

Consider replacement if:

• Major components (engine, alternator) have failed
• Parts are hard to source or discontinued
• You need more power, quieter operation, or inverter technology for electronics

A reputable repair shop can provide an estimate and honest opinion on remaining life vs. replacement cost.

Helpful Tips for Keeping Your Gas Generator Running Smoothly

1. Use fresh, stabilized fuel. Add fuel stabilizer to gasoline and rotate stored fuel every 2–3 months, or as recommended.
2. Run the generator monthly. Let it run for 15–20 minutes under light load to keep the carburetor and seals in good shape.
3. Change oil on schedule. Use the correct grade and keep the level between min and max—not overfilled.
4. Store it properly. Turn off the fuel valve and run the carb dry before long-term storage; cover and keep in a dry, ventilated area.
5. Keep it clean and ventilated. Remove dust/debris, ensure clear airflow, and always run outdoors far from windows and doors.
6. Log maintenance. Keep a simple notebook or phone note with dates for oil changes, plug replacements, and services to stay on track.