Common Reasons Your Generator Won’t Start – 9 Things To Check

A man attempting to start a small gas-powered generator.

A generator can be a beneficial machine to own. Whether you’re preparing for a power outage or planning a camping trip and want power out in nature, a generator can undoubtedly come in handy – that is, if it will startup.

A generator that won’t start serves no purpose, but don’t worry. There are many common reasons your generator won’t start that can be fixed easily.

If you’ve discovered that your generator isn’t revving like it’s supposed to, then you need to troubleshoot it right away. Sometimes, it’s a simple fix such as topping off the fuel, although sometimes replacement parts are required.

Keep reading to learn the top 8 most common reasons your generator won’t start and how to fix it.

Why Won’t My Generator Start?  

There are several common reasons that your generator won’t start. Luckily, most of these issues are relatively easy to fix. 

The Generator Is Low on Fuel

One of the most common reasons a generator won’t start is because there is no or low fuel in the fuel tank. Check the fuel tank. If the levels are low, fill it with fresh gasoline.

It’s also essential to make sure you’re not trying to start your generator with old fuel. Any fuel that is more than two months old must be replaced to avoid potential damage to the engine.

The Engine Is Low on Oil

It’s not just the fuel level that needs to be replenished; sometimes, it’s the oil in the engine. Oil is just as crucial as fuel when it comes to operating your generator.

The oil will need to be replenished after 50 hours of continual use. Brand new generators will need replacement oil within the first 20 hours. Check the oil level and fill as necessary. 

The best way to do this is by using a dipstick to check your generator’s oil level. This is typically found in the crankcase. Make sure you’re using the right oil for your particular generator. Most of the time, you will need to replace filters when replenishing oil levels.

The Choke Is in the Wrong Position

The choke must be in the right position to allow airflow to the carburetor during the startup process. When the choke is too open or too closed, it won’t allow proper airflow.

Double-check that the choke control is closed entirely. However, a generator that was only turned off briefly will need a choke control that is set halfway.

Spark Plugs Need To Be Replaced

Sometimes, there is an issue with the spark plugs. Inspect the spark plugs and look for any signs of damage, such as cracking, burned porcelain, or carbon buildup.

If you see any signs of wear, perform the spark plug test. This is done by turning on the engine and seeing if there is a spark between the terminals. If there is no spark, then the plugs will need replacement. 

Ignition Coil Needs Replacement

The ignition coil works conjointly with the spark plugs. So, if you have checked the spark plugs and ensure that they are functioning, it may be an issue with the ignition coil.

You can check the ignition coil by using an ignition coil tester, like this one for small engines. If it is not working correctly, it will need replacement.

Ram-Pro Inline Spark Tester, Plug Engine Ignition...

Check Price On Amazon

The Carburetor Is Clogged

If none of the other common reasons for a generator that won’t start weren’t the culprit, then it may be a clogged carburetor. A clogged carburetor commonly occurs when fuel is left in the generator.

Over time, the fuel evaporates and creates a thick and sticky substance in the carburetor. To unclog, use a carburetor cleaner or replace the carburetor. 

Air Filter Needs Replacement

A carburetor needs air to function. Therefore, a dirty air filter will not allow the carburetor to work, and thus the generator won’t start. To check the air filter, simply perform a visual check.

If you’re unsure, try removing the air filter and see if the generator starts up. If it revs without the air filter, then you should clean or replace the air filter. 

Don’t leave the generator running without an air filter. 

The Battery Is Dead

Some generators are electric and work with a push to start button or a remote. If you own an electric generator, ensure that the battery is working.

If you suspect the battery is causing the issue, try starting the generator using auxiliary recoil starters (if applicable). If it runs, then you will need to charge your starter battery. 

Generator Troubleshooting Checklist  

If you’re trying to start up your generator with no luck, you need to follow this troubleshooting checklist.

This checklist will allow you to find the problem with your generator. From there, you can do the proper steps to fix the issue and get your generator back on track.

  1. Check the fuel level. You can check the status of fuel in the generator visually. Top up if necessary. However, make sure you are using fresh fuel. Stale oil can be troublesome for a generator.
  2. Check the oil level. This can be checked using a dipstick. If the oil level is low or empty, you will need to replace it with the right oil. Sometimes, you may need to replace the filters.
  3. Check where the choke level is. Sometimes the culprit is a choke level in the incorrect position. It may also be too tight. Check to make sure that it is in the right place.
  4. Inspect the spark plugs. Spark plugs that are damaged or have build up won’t spark. Try turning on the generator and see if any sparks fly.
  5. Make sure the low-oil sensor is working, and the ignition coils are functioning. Both of these are imperative for a properly functioning generator. 
  6. Unplug any electronics during startup. Nothing should be plugged into the generator when it is being revved up. Disconnect any electronics and try starting the generator once more.
  7. Check the battery. Dead batteries won’t turn on a generator. Double-check the battery. If you believe the battery is the suspect of your generator not turning on, charge up the battery, and try again. 
  8. Double-check for clogs. A clogged carburetor won’t be able to rev up a generator. Clean the carburetor and try again.
  9. Lastly, check the air filter. Air is necessary for a generator to start and function. Dirty air filters should be cleaned or replaced.

If you have tried all of these troubleshooting measures and you’re still struggling with a generator that won’t start, it’s time to use the manual that came with your generator.

There should be a section with information regarding your specific model and possible reasons it might not start. 

Can You Jump Start a Generator?

If your generator doesn’t start, you might wonder if it’s possible to jumpstart it as you could a car or another machine that utilizes a battery. The simple answer is yes; you can jumpstart a generator.

It is done the same way as you would jumpstart a vehicle. In fact, you will need a car to jumpstart the generator. Here’s how.

  1. Wear a pair of safety goggles and gloves.
  2. Connect the positive terminal to the car, then to the generator.
  3. Attach the negative terminal to a frame on the generator, then a metal part of the car (not the battery).
  4. Start the car.
  5. Wait a few minutes before trying to start the generator.
  6. If there is no success, try the process once more.
  7. Disconnect the cables, ensuring the positives and negatives do not touch.

If you try to jumpstart the generator and are unsuccessful, then the battery may not be why your generator won’t start. Try following the generator troubleshooting checklist to find what else may be causing the issue with your generator.

Final Thoughts

A generator that won’t start will serve no purpose. Luckily, there are many common problems and solutions that can get your generator up and running again.

Sometimes, it’s as simple as topping off the fuel or oil. Other times, it may mean replacement of the ignition coils, spark plugs, or air filter.