Firman Generator Keep Shutting Off: How To Fix It

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One of my clients has been experiencing trouble starting his Firman generator, as it keeps shutting off.

What could be the reason? 

In most cases, generators shut off and won’t stay running due to several factors. These include bad spark plugs, low oil levels, ignition wire issues, wiring problems, carburetor issues, PCV issues, fuel filter issues, dirty air filters, and more.

In this blog post, I will explain all the reasons and causes why your Firman generator may not stay running and keeps shutting off. I will go into detail about what you need to know and do before considering taking it to a professional. 

So, keep reading and learn about all possible reasons and the best ways to fix your generator and keep it running when you need it.

Reasons Why Your Firman Generator Keeps Shutting Off?

The major reasons why your generator you have been trying to start for a long time keeps shutting off is caused by the carburetor, air filter, spark plug, and the fuel in the tank. 

Apart from the above mentioned, some other reasons include:

  • PCV issues
  • Fuel filter
  • Low oil level
  • Closed fuel valve
  • Wiring problems
  • Ignition wire issues
  • Overheating 
  • Engine seals 

So, let’s get into more detail about how these reasons cause your generator to keep shutting off and what you can do to get it running without shutting off.

Clogged Carburetor 

The carburetor is one of the major factors that causes your firman generator to keep shutting off. The carburetor has probably become clogged due to the accumulation of dirt, debris, and other particles. This clog can significantly impact the flow of fuel, subsequently leading to a decrease in the generator’s performance. 

PCV Issues

The PCV (positive crankcase ventilation) valve helps reduce emissions and prevent oil leaks by venting the pressure from the crankcase. If the PCV valve is clogged, damaged, or missing, it can cause the engine to run poorly, consume more oil, and shut off unexpectedly.

Low oil level

The engine’s oil level is critical for lubrication and cooling. Most Firman generators are manufactured with low oil sensors, and whenever the oil is low, it triggers the sensor, shutting off the generator to prevent damage.

Closed fuel valve

The fuel valve controls the flow of fuel from the tank to the carburetor into the combustion chamber. If the fuel valve is clogged, dirty, or corroded, it can restrict the fuel supply and cause the generator to stall or shut off.

Wiring problems

The wiring system is responsible for transmitting electrical signals and power from the battery, ignition, and alternator to the generator. If the wiring is loose, broken, or short-circuited, it can also cause the generator to malfunction or shut off.

Ignition wire issues

The ignition wire system is responsible for creating a spark that ignites the fuel-air mixture in the engine. If the ignition wire system is faulty, it can cause the generator to fail to start or shut off.

The ignition goes along with the spark plug creating a spark that ignites the fuel-air mixture in the engine. If the spark plug is also dirty, fouled, or damaged, it can cause the engine to misfire, run rough, or shut off. 


Overheating can also be caused by extended use or hot/humid conditions. If not addressed quickly, it can lead to engine damage and eventual automatic shutdown.

Engine seals

The engine seals prevent oil, fuel, and air from leaking out of the engine. If the engine seals are worn, cracked, or broken, they can cause the engine to lose compression, power, and efficiency and shut off.

Air filter

The air filter helps filter the air that enters the engine. If the air filter is dirty, clogged, or wet, it can reduce the airflow and cause the engine to run rich, smoke, or shut off. 

Fuel in the tank 

The fuel in the tank is the source of energy for the generator. If the fuel in the tank is old, contaminated, or insufficient, it can cause the generator to run poorly, sputter, or shut off whenever it enters the carburetor.

RECOMMENDED READ:- Generator Shuts Off After 20 Minutes: Troubleshooting Tips

How To Fix Firman Generator Keeps Shutting Off

Man holding an extension cord trying to start his Firman generator

After knowing the reasons why your generator keeps shutting off, there are some things you can work out yourself to make it stay running such as checking the oil level, spark plug, carburetor, air filter, etc. 

So let’s get in a more detailed way of how you can fix the Firman generator shutting off.

Check out if the fuel valve is opened

The fuel valve is responsible for controlling the fuel from the tank to the carburetor into the combustion chamber. Since it controls the fuel, it might sometimes become clogged due to dirt and other particles.

In that case, you have to check if the fuel is flowing out freely from the tank. You can remove the fuel line from the carburetor or the fuel valve itself and put it in the “ON” position. 

If there’s a free flow of fuel, it means the fuel valve is okay. But if there’s no free flow of fuel from the valve, you have to remove the fuel valve from the tank or wherever it is on your generator and clean it out. 

Additionally, you should also check out the fuel in the tank. If you find out that there’s dirt in the tank while removing the fuel valve, draw out the fuel and wash the tank. Failure to do this will still make the problem continue.

You can also find out how long the fuel has been sitting in the generator tank. If it has been sitting for a longer period of more than 40 days, I recommend you change the fuel and move to the next step.

Check out the carburetor

After you check the fuel valve and the tank and they are okay, you have to check out the carburetor. But before that, you should first check the fuel line for any leakage. If there isn’t, then service your carburetor.

Servicing your carburetor means cleaning it out and in that way, you are to clean it carefully with all its components. All Firman generators don’t use the same carburetor but I assure you that they have the same servicing method.

However, even if you cleaned the carburetor it might not work when it’s supposed to and that’s because the carburetor has been clogged for a long time and no matter what you do, it won’t start running. If it does fortunately run for a while, it will be surging and might get your appliance damaged.

The only way that you can fix this issue and make it run smoothly is for you to change the carburetor if servicing it doesn’t help. 

Additionally, while servicing your generator, you should also check out the air filter if it’s soaked with oil, or if it’s clogged. Whatever happens with the air filter, you can change the filter or clean it thoroughly.

Check out the oil level in your generator

Oil is significant in generators and without it, generators won’t function and will get damaged in a short amount of time. That’s why Firman generator manufacturers invented the low oil level sensor.

The oil sensor helps manage the oil level in the generator. If the generator has low oil, the engine won’t start. And if it does start, it will shut off after some time. 

What you should do is check if you have low oil or if the oil has been sitting for a long. If it has been sitting for long, I will suggest changing the engine oil but if it hasn’t, you can top the oil with a better one.

Other Things You Shouldn’t Do Yourself

A lot of my clients have tried working on their generator above the tips I listed earlier but eventually, they all end up damaging their generator. 

It might be easier to check your spark plug, carburetor, tank, fuel valve, fuel filter, and oil level but for the remaining, you need the help of a generator professional.

Problems like ignition wires, wiring issues, engine seals, PCV issues and the rest need to be done only by a professional because they are more complex than thought. 

But one thing is sure, apart from the ones I urged you to do yourself, the remaining reason listed in this article rarely causes Firman generators to keep shutting off. 


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