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What to Do If Your Generator Won’t Start?

A portable or standby generator is an expensive investment. Whether you use it regularly for work or occasionally during emergencies and power outages, you expect the generator run flawlessly. But sadly, this might not be the case for some generator owners. You fill the fuel tank of the generator, insert the ignition key, twist the key to start it but your generator won’t start.

With some simple troubleshooting steps, you can fix this issue. In this guide, we will explore the reasons why a generator won’t start. After that, we will see some simple fixes.

What is a Generator?

A generator is a machine that converts mechanical energy into electrical energy. It works by using an engine, usually powered by gasoline or diesel, to turn a rotor inside a coil of wire.

This creates a magnetic field that produces an electrical current in the coil. We can then use the electrical energy that the generator produces to power a wide range of electrical devices and equipment.

Generators are very common as backup power sources in homes, shops, and small businesses in case of power outages, or in situations where a reliable source of electricity is necessary but not available from the power grid.

They are also popular on construction sites, at outdoor events, and in other settings where access to electricity is limited.

Generators come in a variety of sizes and types, ranging from small portable models that can be easily moved from place to place, to large industrial models that can power entire buildings or complexes. They are an important tool for providing electricity in situations where it is needed, and for ensuring that critical infrastructure and equipment can continue to operate even during power outages or other disruptions.

Common Problems with Generators

Here are some common problems that can occur with generators.

You can trace back many generator issues to fuel problems, such as running out of fuel, using stale fuel, or clogged fuel filters.

Most modern generators have electric start feature. Hence, all these generators will have a starter battery.

If the generator is electric start, problems with the battery, such as a dead battery or loose connections, can prevent the generator from starting.

Dirty, fouled, or damaged spark plugs can prevent the generator from starting. Low oil levels or dirty oil can cause prevent the generator from starting. Some modern generators have advanced oil level sensors. If the sensor detect low oil level, it will automatically shutdown the generator and prevent it from starting.

A dirty or clogged carburetor can cause the engine to run poorly or not at all. Dirty or clogged air filters can restrict airflow to the engine, causing it to run poorly or not at all.

Overloading the generator with too much power demand can cause it to shut down or damage the generator. Problems with the ignition system, such as a faulty ignition coil or spark plug wire, can prevent the generator from starting.

Mechanical issues with the engine or generator components can cause the generator to stop working or run poorly.

It is important to regularly maintain and service your generator to prevent these problems from occurring and to address them promptly if they do occur.

Regular oil changes, air filter replacements, and fuel system maintenance can help keep your generator in good working condition.

If you are not comfortable working with generators or engines, we highly recommend you seek the help of a qualified professional.

Reasons Why a Generator Won’t Start

There are many possible reasons why a generator won’t start. We mentioned some popular ones here.

Lack of Fuel

An internal combustion engine is the heart of the generator. So, a generator needs fuel to run the engine. If the fuel tank of the generator doesn’t have enough fuel, then the generator won’t start.

Low Oil Level

Another engine-related issue is level of oil. Most generators have an oil level sensor that prevents the engine from starting if the oil level is low.

Dead Battery

Some generator models have starter batteries to help crank the engine (generators with electric starters). Similar to cars and other automobiles with engines, a dead battery won’t start the engine of the generator as well.

Dirty Fuel Filter

A clogged fuel filter can prevent fuel from reaching the engine. Replace the fuel filter if it is dirty.

Stale Fuel

If the generator has been sitting for a long time with fuel in the tank, the fuel may have gone stale and may need to be drained and replaced.

Faulty Spark Plug

If the spark plug is dirty, fouled, or damaged, the generator may not start. Check the spark plug and replace it if necessary.

Faulty Carburetor

The carburetor mixes air and fuel to create the combustion needed to start the engine. If the carburetor is dirty, clogged, or damaged, the engine may not start.

Blocked Air Filter

A dirty or clogged air filter can prevent air from reaching the engine, which is necessary for combustion to occur.

Faulty Ignition System

The ignition system includes the spark plug, ignition coil, and other components that ignite the fuel. A problem with any of these components can prevent the generator from starting.

Mechanical Issues

There may be mechanical issues with the engine, such as a seized piston, that prevent it from starting.

It’s important to troubleshoot the issue thoroughly to determine the root cause and address it accordingly.

How to Fix a Generator That Won’t Start?

Fixing a generator that won’t start will depend on the specific cause of the problem. Here are some general steps you can take to troubleshoot and fix the issue

Check the fuel level and valve. Ensure that the fuel tank has enough fuel and that the fuel valve is turned on.

If your generator is electric start, check the battery and charge it if necessary. If the battery is dead beyond recharge capabilities, replace it.

Replace the fuel filter if the fuel filter is clogged or dirty. If the fuel has gone stale or has been sitting for a long time, drain and replace it with fresh fuel.

Check the spark plug and replace it if it is dirty, fouled, or damaged. Check the oil level. Make sure the oil level is adequate. Most generators have an oil level sensor that prevents the engine from starting if the oil level is too low.

If the carburetor is dirty or clogged, clean it or have it cleaned by a professional. Replace the air filter if it is dirty or clogged.

Check the ignition coil, spark plug wire, and other ignition components for damage. Replace any faulty parts. Address the mechanical issues. If the problem is a mechanical issue, such as a seized piston, have it repaired by a professional.

It is important to always follow the manufacturer’s instructions when troubleshooting and fixing a generator.


A generator is essentially an internal combustion engine that produces electricity. There are a bunch of other components but the engine is the main one. Due to the mechanical nature of the generator, it can have several problems.

One common problem is generator won’t start no matter what you do. In this guide, we saw the popular reasons why a generator won’t start and also saw some simple troubleshooting steps.

We hope that this guide could help you understand the problem a little better and also how to overcome it. if you feel we missed something or want us to add anything, do let us know in the comments section below. It will help not only us but also other readers.

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