If Your Generator Won’t Start (Generator Troubleshooting)

For some folks, a portable generator might be a rare tool to use. However, when you need to use it, finding out that the tool is not working could be quiet annoying. Especially when you are going through an emergency situation, such as power loss for extreme weather.

If you meet one of such situations where your generator won’t start, then what is the solution? Well, there is a checklist of things that you should try. Some cases will solve right after a simple troubleshooting process. Let’s talk about some troubleshooting process below.

Before starting, make sure to go through the manual of your generator.

If Your Generator Won't Start

Common Scenarios When A Generator Won’t Start!

It’s Running Out of Oil or Gas

Have a look at the crankcase. Check for the oil level. If it’s low then this might be the reason why your portable generator won’t start.

Add oil once the level is low. Sometimes when you run the generator in an uneven surface, there might be problems with low oil sensor. It may show you low levels even when it has enough oil.

Also, be sure to have a look at the gas tank. There should be enough amount of gasoline within the tank. If it’s running out of gas, then make sure to add fresh gasoline in it.

Do this if you want to avoid hard starts and clogs. Never go for stale or old gasoline for the generator. If the stored gasoline is more than two months old, don’t use it.

Wrong Position of Choke Lever

When you are going for startups, make sure the choke lever is set to close. Once the engine starts to warm up, make it open. There are different types of generator that use various positioning for this choke lever.

Some generators will have it over the air filter directly above on its side. While there are a few models that hold the choke lever on power control knob. For example, the WEN inverter series. No matter which one you have, make sure to keep it closed. Some may also refer it to start.

As soon as the engine ignites, you can put choke on OPEN/RUN/ON position. If you were already running the engine for a while before refueling then it might be warm enough. In that case, you can set the choke lever to Run or Open for starting.

Closed/Clogged Fuel Valve

Sometimes you have a generator that is full of fuel. However, fuel might not be reaching the carburetor. There might be some issue with the fuel line or valve. This line is in responsibility of controlling and following the fuel from tank to carburetor.

You have to make sure the OPEN operation is set to let fuel flow in proper channels. If you have already put it on OPEN but yet the fuel is not flowing correctly then there are things to do.

There might be a vacuum relief valve on top of the tank. This might not be opened and so the problem is showing up.

You need to unplug the outlet hose. It is on the fuel valves’ intake side. Now you should be able to see if the fuel is running freely or not. You should keep a bucket with you for these steps.

This way you’ll be able to find out if the valve is clogged and which part exactly is making a problem. You should also check the in-line fuel filter. Most of the time it’s located between carburetor and fuel tank. Make sure it is not blocked.

Clogged/Air-locked Carburetor

Sometimes we don’t bother about storing generator for a long time without using it. If you don’t drain the carburetor before then probably it will get clogged by old gasoline. However, you can still fix it.

Turn off the fuel valve. Now you need to open the carburetor drain at very bottom. Clean out any stale fuel you can see thoroughly. There is a brass nozzle you might see in central stem known as the main jet. Make sure to clean it with a needle as well.

You can simply avoid this situation by turning on your generator every once in a month. Without draining the gas, never store it for long periods.

Replacing Spark Plug

Sometimes the spark plug might go through deposit and dirt buildup. Generators often come with spark plug wrench or you can simply buy one. Use it to remove the spark plug and check for any deposit. You can use a small knife or similar gear to thoroughly clean that area.

There should be an exact gap in the electrode for your particular generator model. Check it on manual and makes sure the gap is right.

Now hold the spark plug’s body to engine crankcase. Simply pull the recoil starter. If you see a blue color strong spark then the coil is still good and usable. However, if you see no or weak spark then you need to do a few more steps

Eliminate the spark plug and cap. Place the wire of spark plug end near to engine’s body. Now pull the starter once again and see ignition coil. If you see sparks between the boot and engine then this plug needs replacement. If you can’t see any sparks yet, change the ignition coil.

Problematic Low-Oil Sensor

If you believe the spark plug is working properly then it might be low-oil sensor. Look for the wire coming from crankcase and remove it. This wire connects the low oil sensor to engine.

Position of this wire might not be the same in different generators. Check if the generator starts right after removing wire. If it does, then the low-oil sensor needs repairing.

There are cases where you can try running the engine for a few time with unplugged wires and problems resolves. If this does not work then you may need to tear-down in engine for an oil-sensor replacement.

Dead Batteries

Sometimes the whole house generator won’t start when battery is dead. Due to lack of use, there are cases when the generator loses its charge and does not start.

You can simply use a pull starter and add juice back into the battery. This will help to start it in no time. If you can’t find recoil starter then use some other method. You can get a third-party battery charger.

Plugged in Electronics While Start Up

You should make sure that no electronic device is plugged in while starting up the generator. This might be a reason why the generator isn’t starting. You should turn off everything including vacant extension cords.

Air Filter!

Sometimes the air filter meets defect. So, it won’t let the carburettor to have necessary amount of air. This might be a barrier for proper ignition. For such cases, check the side of your generator and open up air filter. There should be a spongy air filter elements within. You should clean the thing or replace if necessary.

Watch This:


This troubleshooting is basically a general overview of different styles of generators. You can refer to the manual of your particular generator for a specific breakdown. If you still find trouble starting the generator then go for expert help. You would need a technician for a deep checking. Good Luck!

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