While a generator is a great item to have on hand in case of a power outage, it doesn’t do much good when it doesn’t work right. You often don’t realize the problem until you actually need your generator.
To help you quickly find your problem, I have put together charts to troubleshoot common Generac generator problems. You will also find links to more detailed information for each problem.
The most common Generac generator problems are:
- Generac generator won’t start
- Generac generator starts and then dies
- Generac generator is leaking gas
- Generac 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 Generac operator’s manual.
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Follow all safety instructions provided in your equipment operator’s manual prior to 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.
Generac Generator Won’t Start
When you begin looking for a reason your generator won’t start and it won’t even turn over, check the starter recoil on a manual start and the battery, ignition switch, and starter solenoid on a model with an electric start.
If the generator turns over and just won’t start, look for issues that may cause a fuel, air, or spark restriction. This may be a plugged fuel filter, clogged fuel lines, dirty carburetor, bad fuel tank vent, bad spark plug, or faulty ignition coil.
Check out this information for more items that can prevent your Generac from starting:
Detailed information can be found at:
Reasons a Generac 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 Generac 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 Generac 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. |
Generac Generator Starts and Then Dies
Many of the reasons that cause a Generac generator from starting are the same as those that will cause it to stop running after you get it started.
Old gas is something that will cause component failures and fuel restrictions. It can evaporate leaving behind gummy residues in the fuel lines, fuel filter, and carburetor.
A bad or clogged fuel tank vent can also cause a fuel restriction. When the engine doesn’t get enough fuel, it will run sluggishly and possibly die.
You’ll also want to look for items that can restrict airflow or spark. These include a plugged air filter, plugged spark arrestor, dirty spark plug, or faulty ignition coil.
Detailed information can be found at:
Generac Generator Starts Then Dies
| 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 Generac 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. |
Generac Generator is Leaking Gas
You may have a gas smell coming from your Generac 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 Generac 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. |
Generac Generator is Bogs Down Under Load
A Generac generator that loses power 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 Generac 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. |