While keeping your generator well-maintained by performing routine maintenance can help minimize problems, when you own a generator long enough you can expect to run into problems due to wear from normal usage.
To help you quickly find the cause of your problem so you can fix it, I have put together tables to troubleshoot common generator problems. You will also find links to more detailed information on each problem.
The most common generator problems are:
- Generator won’t start
- Generator starts and then dies
- Generator is leaking gas
- Generator bogs down under load
Take caution when performing repairs. Always remove the spark plug wire and wait for the engine to cool. Follow all safety precautions found in the operator’s manual.
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Follow all safety instructions provided in your equipment operator’s manual before diagnosing, repairing, or operating. Consult a professional if you don’t have the skills, or knowledge or are not in the condition to perform the repair safely.
Won’t Start
When troubleshooting your generator’s starting problem, look for items that are keeping the engine from getting sufficient air, fuel, and spark. Spark ignites the fuel and air mixture to start the engine.
If your generator won’t turn over, check the starter recoil on a manual start generator or the battery, starter solenoid, and wiring on an electric start generator.
Detailed information can be found at:
Reasons a Generator Won’t Start: Solved!
| Cause | Reason for Problem | Solution |
| Empty fuel tank | No gas in the fuel tank | Fill with fresh fuel. |
| Bad or old fuel | Fuel breaks down over time making your fuel less efficient and prone to clogging the fuel system and damaging components. | Drain the fuel tank. Fill it with fresh fuel and a fuel additive like Sea Foam to stabilize gas and clean the fuel system. |
| Bad fuel tank vent in fuel cap or another type of fuel tank vent depending on your model. | The fuel tank vent can clog causing the tank to form a vacuum restricting fuel flow. | Replace a plugged or bad gas cap or another type of fuel tank vent that may be found on the top of your fuel tank. |
| Bad spark plug | Excessively dirty or broken spark plug; bad connection; not gapped correctly. | Replace with a new spark plug, secure connections, and ensure it is gapped to manufacturer specifications. |
| Bad ignition coil | Your generator will not start when either the ignition coil is bad because it won’t provide voltage to the spark plug to provide a spark. | Test and replace a bad ignition coil. |
| Plugged air filter | Dirt can plug the air filter preventing airflow from getting to the carburetor. | Remove the filter and clean it. Replace the filter if it is in bad condition. |
| Plugged fuel filter | A dirty fuel filter will restrict fuel flow. | Replace the fuel filter. |
| Blocked fuel lines | Bad fuel deposits and dirt can build up and clog the fuel lines preventing the engine from getting the required fuel | Use a carburetor cleaner and compressed air to remove the clog from the fuel line. Replace the line if necessary. |
| Dirty carburetor | The carburetor can become dirty and clogged due to bad fuel and ethanol deposits preventing fuel flow | Clean the components making up the carburetor. Replace if needed. |
| Low engine oil level | A sensor on a generator protects the engine by not allowing it to run when the engine oil level is low. | Place on a flat surface and add oil until it is at the full level as indicated on the oil dipstick. |
| Incorrect choke setting or stuck choke | The choke must be on to restrict airflow when starting a cold engine. It must then be adjusted to off once the engine is warm. | Make sure the choke setting is correct. If its setting is correct, check that the choke linkage is working properly and the choke is not sticking. |
| Broken starter recoil | A pull start generator may have a damaged or broken recoil preventing the recoil to initiate starting your engine | Check the recoil to see if it can be restrung or if broken parts can be replaced. Replace the recoil assembly if needed. |
| Bad battery, loose wires, dirty terminals (electric start) | A low charge on a battery will prevent the generator from starting. | Charge the battery. If the battery fails to hold a charge, replace the battery. |
| Faulty starter solenoid (electric start) | The internal spring may become weak or the copper plate may corrode causing solenoid failure. | Bypass the solenoid to isolate it as the reason for failure. Replace if it is faulty. |
| Bad ignition switch (electric start) | The switch is faulty on models with an electric start. | Test the switch using a multimeter. Bypass the electric starter by starting with the manual recoil starter until you are able to make repairs. |
Starts and Then Dies
Many of the items listed above for a starting problem can also be the cause of your generator dying.
On most generators used today, a low engine oil level can set off a sensor that stops the engine to protect it from damage.
Other common reasons for a generator dying are fuel and airflow restrictions.
Detailed information can be found at:
Reasons a Generator Starts and Stops Running
| Cause | Reason for Problem | Solution |
| Bad fuel | Fuel breaks down over time making your fuel less efficient and prone to clogging the fuel system and engine damage. | Drain the fuel tank and fill it with fresh fuel. Use a fuel additive like Sea Foam to stabilize the fuel and assist with cleaning the fuel system. |
| Plugged fuel filter | A dirty fuel filter will restrict fuel to the carburetor. | Replace a plugged fuel filter. |
| Plugged air filter | Dirt and grass can plug the air filter preventing airflow | Remove the filter and clean it. Replace the filter if it is in bad condition. |
| Clogged fuel lines | Bad fuel deposits and dirt can build up and clog the fuel lines preventing the engine from getting the required fuel. | Use a carb cleaner and compressed air to clear the clog out of the fuel line. |
| Dirty carburetor | The carburetor can become dirty and clogged due to bad fuel and ethanol deposits preventing fuel flow. | Clean all of the components making up the carburetor. Replace if needed. |
| Bad Gas Cap / Fuel Tank Vent | The fuel tank vent can clog causing the tank to form a vacuum restricting fuel flow. | Replace a plugged or bad gas cap or another type of fuel tank vent that may be found on the top of your fuel tank. |
| Dirty Spark Plug | A dirty spark plug may provide an intermittent spark. | Replace a very dirty spark plug. Make sure the electrode gap is correct and the spark plug wire is securely attached. |
| Bad Ignition Coil | When the ignition coil fails it won’t provide voltage to the spark plug. | Test the ignition coil using an ohmmeter. Replace an ignition coil when you find a break in the continuity. |
| Low Engine Oil Level | A sensor on a generator protects the engine by not allowing it to run when the engine oil level is low. | Place on a flat surface and add oil until it is at the full level as indicated on the oil dipstick. |
Leaking Gas
You may have a gas smell coming from your generator. Fumes are harmful and the leak must be found before you continue to run the generator.
A carburetor is a likely place where a generator will begin leaking. This is because the carburetor bowl gasket may fail to seal properly or internal parts will stick allowing too much fuel into the bowl and causing it to overflow.
Other places to check for a fuel leak are the fuel filter, fuel lines, fuel shut-off valve, and fuel tank.
Detailed information can be found at:
This is Where Your Generator is Leaking Gas
| Reason for Problem | Solution | |
|---|---|---|
| Dirty carburetor | The carburetor can collect a buildup of substances remaining from old gas that can cause blockages or parts failures. | Clean the carburetor and replace any damaged parts. |
| Weak fuel filter | The plastic on the filter can degrade causing it to leak at the seams. | Replace the fuel filter. |
| Fuel tank | A metal tank can develop a rust hole. A poly tank can leak at the seams of the tank. | Replace the fuel tank. Sometimes, a rust hole can be repaired if you can no longer find a replacement tank. |
| Fuel shut-off valve | Metal and plastic shut-off valves are prone to leaking. | Replace the shut-off valve. |
| Old fuel lines | Fuel lines become dry and cracked causing gas to leak. | Replace the fuel lines. Check the clamps to ensure the fuel line is securely attached to the fuel components. |
Bogs Down Under Load
A generator that loses power and bogs down when it is under load is most likely the result of an air or fuel restriction.
It may also be due to trying to power more items than your generator is designed to handle.
Detailed information can be found at:
This is Why Your Generator Bogs Down Under Load
| Cause | Reason for Problem | Solution |
| Too Much Load Applied | Overloading the generator by plugging in more items than the generator’s load limit will cause it to bog down. | Check the generator load limit. Add up the wattage for the items that will be plugged in at one time to ensure it doesn’t exceed the load limit. |
| Bad or Old fuel | Fuel breaks down over time making it prone to clogging the fuel system and damaging components. | Drain the fuel tank and fill it with fresh fuel. Use a fuel additive like Sea Foam to stabilize the fuel and assist with cleaning the fuel system. |
| Clogged fuel filter | A dirty fuel filter will restrict fuel to the carburetor. | Replace a clogged fuel filter. |
| Plugged air filter | Dirt and grass can plug the air filter preventing airflow. | Remove the filter and clean it. Replace the filter if it is in bad condition. |
| Incorrect Choke Setting / Stuck Choke | The choke is used to restrict air to start a cold engine. When it isn’t set right, the air needed to run the generator will be restricted. | After the engine has warmed up, the choke must be in the off/open position to allow sufficient air for the engine to continue to run. |
| Plugged spark arrestor | A buildup of material in the spark arrestor screen will prevent air from moving through the exhaust. | Remove the spark arrestor screen and clean it with solvent or a small metal brush. Replace a screen that is damaged. |
| Dirty carburetor | The carburetor can become dirty and clogged due to bad fuel and ethanol deposits preventing fuel flow | Clean all of the components making up the carburetor. Replace if needed. |