Generator Won’t Start? – 9 Reasons One Should Look At

The backup generator market has increased from 3% to 5% since 2013 due to frequent and prolonged power outages caused by the increasing number of natural disasters.

While people are purchasing portable generators for backup power, camping, and tailgating, not everyone knows how to maintain them in case the generator won’t start.

Whether it’s a lack of power, strange noises, or no response at all, there are a few common issues that can prevent your generator from starting.

In this article, we’ll take a look at some of the most common reasons why generators won’t start, and provide some easy troubleshooting tips to help you get your generator back up and running in no time.

Don’t let a broken generator ruin your day, read on to find out how to fix the problem. Here are 9 reasons your generator won’t start.

9 Reasons Your Generator Won’t Start

1. Low Oil

The engine oil lubricates the moving parts and helps to keep the engine cool. Most modern generators are equipped with low-oil shutoff features that will automatically shut down the generator if there is not enough oil in the engine to prevent malfunctioning.

But, there are some models in the market that are not equipped with such features. So, you gotta be careful and change the oil once every 40 to 50 hours (depending on the model. Check the user manual).

If you forgot to do so, the generator won’t start. Oil level is the first you should check before jumping to conclusions.

My SANCO 2000W doesn’t has a low-oil sensor, so I always check the oil whenever it fails to start.

2. Low on Fuel

A generator needs a certain amount of fuel to run. If the generator is out of fuel, it will not be able to start. To check the fuel level, locate the fuel gauge on the generator and see if it needs to be refilled.

But, not always. Sometimes uneven surfaces could also be the reason. The fuel tends to slide down the other where the ignition doesn’t work. Place your generator on an even surface and try to start it again.

3. Dead Battery

If the generator won’t start and makes no noise at all, the battery may be dead. That is we always use the trickle charge method to keep it alive.

The generator may have a battery for the electric starter, which is used to turn the engine over when starting.

To check the battery, locate the battery on the generator, and use a voltmeter to check the voltage. If the voltage is low, the battery may need to be charged or replaced.

4. Choke is in the Wrong Position

The choke is used to regulate airflow into the carburetor when you start the machine. If your generator starts to vibrate strangely and doesn’t start properly, maybe the choke is in the wrong position.

In the cold, close the choke and start the generator, run it for 30 minutes, and then open the choke. This method is used to quickly warm the engine.

If the generator has already been used recently, close the choke halfway then start the engine. You can close it after 20 seconds or so.

The generator with an electric start feature comes with auto-choke.

5. Clogged Air Filter

An air filter is responsible for keeping debris and impurities out of the fuel system.

If the air filter becomes clogged, it can prevent fuel from reaching the engine, causing it to not start.

To check the fuel filter, locate it on the generator and remove it. Inspect it to see if it needs to be cleaned or replaced. If it needs a proper cleaning, make sure to rub it off nicely so that no debrief or dust remains.

Air filters should be replaced once every 6 months even if they are properly cleaned. Read this generator air filter research if you want more insights on the topic.

6. Problems with Spark Plug

Overtime deposits and buildup can appear on the spark plug preventing it from igniting the air-fuel mixture in the engine. If the spark plug is out of commission, the engine won’t start.

With the help of a spark plug wrench, remove the spark plug and check if the surface is burned or black.

Use gasoline and a brush to clean off the buildup. You can also use a carb cleaner, porcelain, or broken electrodes. Now check if it is working or not.

Steps to Test a Spark Plug

  • Hold it close to the crankcase.
  • Don’t screw it in yet.
  • Try to start the generator using manual recoil. Give it some tries.
  • If the spark is strong with blue color, then the spark plug is OK to work with.
  • If the sparks are weaker, then it needs to be replaced.
  • If there are no sparks at all, there is a problem with the ignition coil.

7. Clogged Carburetor

If you haven’t used your generator in a month or so, make sure to drain the excess oil from the carburetor because old stored fuel clogs the carburetor making it difficult for new fuel to get through.

Close the fuel valve and remove the bowl at the bottom of the carburetor to unclog it. Clean the brass nozzle found in the main central system (main jet) with a needle or safety pin. Then, use gasoline, a brush, and a towel to clean the fuel debrief.

Recommended Guide: Generator power surge.

8. Clogged Fuel Valve

A clogged fuel valve can prevent a generator from starting by preventing fuel from flowing into the carburetor or fuel injectors. The fuel valve is used to regulate the flow of fuel into the engine and can become clogged with debris or sediment over time.

This can cause the valve to become stuck in the closed position, preventing fuel from flowing into the engine. This lack of fuel will prevent the generator from starting.

First of all, check if the fuel valve is positioned toward the open position. To check if the fuel valve is clogged, you can remove the valve from the generator and check for any blockages or debris.

You can also try to manually open and close the valve to see if it moves freely. If the valve is clogged, it will need to be cleaned or replaced. In some cases, it might also require fuel tank cleaning or replacement.

9. Malfunctioned Low Oil Sensor

Not all generators have low oil sensors but if the machine has one a malfunctioning low oil sensor could be another reason for a generator not starting.

The low oil sensor is a device that is designed to detect when the oil level in the generator’s oil tank is low.

If the sensor is not working properly, it may not send the correct signal to the generator’s control panel, indicating that there is enough oil in the tank, causing the generator to shut down to prevent damage to the engine.

The warning light or error code may pop up, which indicates the low oil level, and the generator will not start.

To check if the low oil sensor is the cause of the generator not starting, you should check the oil level in the generator’s tank to ensure that it is at the correct level.

If the oil level is correct and the still does not start, then the low oil sensor may be malfunctioning and it should be checked or replaced.

Check out our informative article If your generator is starting and running but not producing power.

Loss of residual magnetism could also be a reason your generator cranks but won’t start. In that, check your article about how to flash a generator if it doesn’t start.

Frequently Asked Questions (FAQs)

Why won’t my generator start?

There are several possible reasons why a generator may not start, including a clogged fuel valve, dead battery, faulty spark plug, malfunctioning starter motor, or a malfunctioning low oil sensor.

How do I know if my generator’s fuel valve is clogged?

To check if the fuel valve is clogged, you can remove the valve from the generator and check for any blockages or debris. You can also try to manually open and close the valve to see if it moves freely.

How do I check if my generator’s low oil sensor is malfunctioning?

To check if the low oil sensor is the cause of the generator not starting, you should check the oil level in the generator’s tank to ensure that it is at the correct level.

If the oil level is low, you should add oil to the tank and see if the generator starts.

What should I do if my generator won’t start?

If your generator doesn’t start, you should first check the fuel valve, battery, spark plug, and starter motor. If these are all in working order, you should then check the oil level and low oil sensor.



Fareed, the highly skilled electrical expert, boasts 5 years of extensive experience in proficiently maintaining, repairing, diagnosing, and installing a diverse range of electrical systems.

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