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10 Common Reasons Your Generator Won't Start

10 Common Reasons Your Generator Won't Start

So your generator is having some problems. Don’t worry: we are going to get through this together. Just breathe easy, and follow these simple instructions to help diagnose your unit’s problems.

1) It’s low on oil

Check the oil level in the crankcase. Add oil if the level is low. Keep in mind that attempting to run the generator on an uneven surface might cause the low-oil sensor to trigger despite there being enough oil. 

2) It’s out of gas

Check the gas tank to make sure a sufficient amount of gasoline remains in the tank. Add fresh gasoline when necessary (to avoid clogs and hard starts, do not use old or stale gasoline. If the gasoline is older than two months, replace it with fresh gasoline).

3) The choke lever is in the wrong position

The choke of any engine should be set to “closed” during startups and then moved to “open” once the engine warms up. Depending on the style of your generator, this choke lever may be positioned in a few different places. On many generators, it can be found directly above the air filter on the side of the unit. On others, the choke is builtin to the power control knob (such as with the WEN Inverter series). Either way, it should be set to closed (also referred to as the start or the choke position) when starting the generator. Once the engine ignites, move the choke to the ON/RUN/OPEN position for operation. If the engine is already warm (for instance, if it was running for a while and you are refueling), the choke lever should be set to the RUN (open) position for starting.

4) The fuel valve is closed or clogged

If the gas tank is full, but no fuel is getting to the carburetor, there may be a problem with the fuel line or fuel valve. The fuel valve controls the flow of fuel from the gas tank to the carburetor. Make sure that this is set to OPEN to allow fuel to flow into the proper channels. If the valve is set to OPEN but the fuel still does not properly flow, you can do two things. First of all, if there is a vacuum relief valve on top of the gas tank, make sure that it has been opened. Secondly, unplug the outlet hose from the intake side of the fuel valve to see if gasoline is freely flowing or not (have a bucket ready in case the gas flows fine). This will help you determine what part of the fuel line (if any) is clogged up. If there is an in-line fuel filter between the fuel valve and carburetor, also check it to make sure it is not blocked.

5) The carburetor is clogged or air locked

If you stored your generator for a long period of time without first draining the carburetor, the odds are high that it may be clogged by old gasoline. To fix this, shut off the fuel valve, and then open the carburetor drain found at the bottom of the carburetor’s bowl. If this still doesn’t work, you can remove the entire bowl from the bottom of the carburetor and clean out any stale fuel. Clean out the main jet (the brass nozzle found in the central stem) with a needle. To avoid this in the future, try to run your generator at least once a month, and never store it for long periods of time without draining the gas tank and the carburetor first. For a video guide on changing your generator’s carburetor, click here.

6) The spark plug needs to be replaced

Overtime, deposits and buildup can appear on the spark plug. To check this, use the spark plug wrench included with your WEN generator to remove the spark plug and check for deposits. Clean the spark plug using a small knife or a similar tool as needed. Make sure the electrode is properly gapped (check the specifications page of your manual to see the proper gap for your particular model). To test the plug, pull the recoil starter while holding the spark plug’s body to the engine crankcase. If the sparks are strong with a blue color, then the ignition coil is good. If there is no spark or if the spark appears weak, remove the spark plug and cap. Put the end of the spark plug wire near the engine’s body and pull the recoil starter to check the ignition coil. If there are now sparks appearing between the spark plug boot and engine, then the spark plug needs to be replaced. If there are no sparks, the ignition coil may need to be replaced.

7) The low-oil sensor isn’t working properly

If the spark plug is properly gapped, deposit-free, and still not igniting, it may be that the low-oil sensor isn’t working correctly. To check this, disconnect the wire coming from the side of the crankcase - usually, it's a black, yellow, or black-and-yellow wire; see the images below. The location of this wire will vary slightly from generator to generator. If the generator starts once this has been unplugged, then the oil sensor is not working. Many times, running the engine with this unplugged for several minutes before reconnecting the oil sensor wire will resolve the problem. Otherwise, the engine may require a complete tear-down in order to replace the oil sensor. Also check out our helpful video on how to disconnect your oil sensor.

8) The battery is dead

For electric start generators, the battery may lose its charge over time due to a lack of use. If this happens, simply start the generator using the pull starter to add juice back into the battery. If a recoil starter is unavailable on the unit, you may need to try alternative methods, such as a third-party battery charger.

9) Electronics are plugged in during startup

Always make sure all electrical devices have been unplugged before starting the generator. You should never have anything plugged into the generator during startups, including vacant extension cords.

10) Check the air filter

The air filter may need to be cleaned or replaced to let the necessary amount of air into the carburetor for ignition. Open up the air filter housing on the side of the generator and check the spongy air filter element inside. Clean or replace as needed. For video instructions on checking and changing a generator’s air filter, click here, or check out our handy video on replacing the air filter assembly.


Keep in mind, this is a general overview for generators of all shapes, styles and sizes. For a more specific breakdown of recommended starting and troubleshooting guidelines, refer to the manual of your specific model of generator. After all this, if you are still having trouble getting your generator started, feel free to give us a call at 1-847-429-9263 (M-F 8AM to 5PM CST) or drop us a message here to talk to our friendly and knowledgeable technical support team.

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Comments

Xolani Gumede - April 25, 2024

Hi guys very interesting topics

Al-Mustapha Imoyaseh - April 25, 2024

I turned on my generator only to come back and meet it turned off. I tried turning it back on but it won’t even turn

Mr. G. Rua - April 25, 2024

Hello, I have a Wen 2350, It is about a year old and I run it about once a month, I installed an hour meter and it only has about 8 hrs run time so far, so it’s basically new but has always had this problem, the oil is so clean I can’t see it on the Magnetic dip stick.

I open the gas valve, pull the choke, wait about 20 seconds to let the fuel run into the carb, and it starts first pull every time. It runs fine, and provides power, it will run for about 25 minutes and then act like it’s running out of fuel and shut down.

There’s fuel in the tank, I took the gas cap apart and ran a thin wire through the check valve that allows air into the tank and thought it was fixed but it still did the same thing,

I thought maybe the heat was causing the fuel line to kink and cut the fuel off but when I opened up the side panel it was fine.

Have you ever encountered a problem like this before?

Dennis Veturi - April 25, 2024

I don’t understand why y’all got to make it so complicated to answer one simple question a diagram for the electronic ignition connection to the module underneath the hood of the generator y’all make no sense no wonder I’ve got rid of this generator you sell a product and you don’t even leave no service manuals or whatsoever on the line for it unbelievable good day

Doeko Kline - April 25, 2024

Ran perfect last year for 4 Hours. This year tried to start and appears to have no spark. Checked the plug and it was ok.

Dean Smith - April 25, 2024

Electric start quit working. Pull start fires generator right up and runs perfect. Any suggestions?

Jose Alvarez - April 25, 2024

Why is my pull cord getting stuck on my wen invert generator

Jason Brown - April 25, 2024

Hello. I ran my 2000w in the cold (20° F) it started to sputter, so I brought it inside to warm up. The next morning it will not start at all… Nothing. Now it’s not getting spark. Please help, this is my only source of power.

Ed Holland - April 25, 2024

One thing to be sure to check if your generator won’t start is if there is water in the gas tank. It is more common than you think. Disconnect the fuel line from the carb and drai some into a container. If you can see liquid separation, then you have water, and need to drain the tank completely and fill with fresh gas. Put a little methyl hydrate in there to eat up the rest of the water and prevent fuel line freezing in the winter.

jamjam - September 5, 2020

it’s a small tiger generator. it was perfectly alright at first but it needed fuelling so we offed it to add some fuel but trying to on it back, it didn’t on again so we are thinking it’s because the fuel valve was not closed but could that be
the issue? please asal solution is needed

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