Generator Won’t Start: 11 Common Reasons

When a generator doesn’t start, most users will check the fuel, spark plugs, and battery terminals. If all these are working, they assume the generator is dead, and all the only option available is taking it to the mechanic for troubleshooting and repair. What I tell you there is more to your generator not starting.


As you well know, generators are complex machines. Most of the time, the complex machine have simple problems requiring simple solutions. If your generator won’t start, don’t be worried. I have a list of popular and most common problems that I will give you in this post, followed by their solutions. Read on to know what they are and how you can solve them.


1) Out of gas


One thing that is quite obvious when a generator won’t start is it running out of gas. It’s worth checking to make sure there is enough gas to start the generator and keep it running. If you’re using a propane-fueled generator, the tank weight might make you think you have enough fuel. Check it out to ensure there is enough gas, and the valves both on the tank and tubing are open.


Another thing, when using stale gasoline, something older that than two months, can cause stating issues to your generator might even cause damage to the engine. If you some of the stale gas remaining in the fuel tank, remember to empty it, including the carburetor. Use the necessary emptying kit to remove the bad fuel correctly and safely. Refill it with fresh gas, and be sure to use it.


2) Low oil


One of the reasons your generator won’t start might be it is low on oil. The gas is responsible for running the generator engine for it to start. Check the oil level in your generator crankcase. Remember, if you’re attempting to run your generator on an uneven surface, the low end might trigger the low-oil sensor despite your generator having enough oil.


3) Malfunctioning of Low Oil Sensor


The low-oil sensor is a complex generator maintenance piece that protects the generator by preventing it from running when the oil is too low. If it malfunctions with the generator having enough oil, it might keep it from starting.


To check if the low-oil sensor is the cause of the starting problems, you need to disconnect the low-oil sensor by unplugging the wire running out of the generator engine’s crankcase. If your generator starts after you’ve disconnected the low-oil sensor, it might be the culprit.


It does usually work when put back in again after leaving the generator running for a few minutes. However, if it doesn’t, then it will need replacement. I will admit it’s time-consuming as you’ve to take the some of the generator engines apart.


You can never remove the generator low oil sensor to mask the problem. Running the generator without it can lead to severe damage if the engine runs dry. It can also pose a significant hazard. Before you disconnect the sensor, make sure you top off the oil and the filters checked for clogging.


4) Issues with the battery


If you’re generator is using an electric starter, be it a push-button, a remote, or a switch, you have to check the battery of the starting problems if it doesn’t start. Like any car, if the generator battery runs out, the electric starter won’t work.


One way and probably the easiest way to troubleshoot electric start problems is to use the auxiliary recoil starter if there is one. If the generator starts with it, you need to charge up the electric starter’s battery using the battery charger and the 12-volt DC outlet on the generator.


If your generator doesn’t have a recoil starter, charge the battery. You can use your car’s 12-volt DC outlet or get a proper AC battery charger. An alternative method is to use jumper cables to start your generator using the car battery. The process is the same as that of jump-starting a car.


If none of these methods doesn’t work, then it’s probably your generator battery is dead and will need a better replacement.


5) Spark plug issue


As time goes by, your generator spark plug can get deposits and buildups. If your generator won’t start, the issue might also be that the spark plug is dirty, not creating the sparks that ignite the fuel. You should check it out.


The generator might come with a spark plug wrench included in the package to use to remove it. If not, get one and remove the spark plug, clean it using steel wire, a small knife, or any useful tool. Ensure the plug electrode is gapped right. You can check for the manual’s specifications on the manual to see the right gap for the spark plug model.


Testing the plug is accessible. Pull the recoil starter while you hold the plug’s body to the engine crankcase. Monitor the sparks. If they are strong and with blue color, your plug is all good. However, if there are no sparks or appear to be weak, remove the spark plug and cap it.


Put the spark plug wire end near the engine body and pull the recoil starter to check the generator ignition coil. Your spark plug needs replacement if you get sparks between the spark plug boot and the generator engine. If no sparks, your generator ignition coil needs replacement.


6) Wrong choke lever positioning


If you’re new to generator things, your engine’s choke must be closed during startup and moved to open when the engine warms up. The position of the chock lever might be different depending on the generator style or model.


For most generators, it can be found directly above the generator air filter on its side unit. You will find the choke built-in to the generator power control knob on other models, most on the inverter series.


Wherever it is, it’s best you keep it closed while you try to start the generator. And once the engine starts and warms up, you can turn on the choke for operation.


7) Clogged or closed fuel valve


If the generator fuel tank is full, but fuel is not getting to the carburetor, the fuel valve or fuel line might be the issue. The generator fuel valve controls the gas from the tank to the carburetor. It’s best you keep it open while starting the generator to allow the fuel to flow in the right channels. If the valve is open and no fuel is flowing, there are two things you can do:


First, the fuel might not be flowing because the vacuum relief valve on top of the fuel tank is shut. You have to open it.

Second, check any clogging on the fuel valve by removing the tank intake outlet hose. Get a bucket ready, just in case the gas is flowing fine.

If there’s an inline filter between the carburetor and the fuel valve, check it out to ensure it’s not blocked.


8) Clogged or air locked carburetor


If you’re generator rested for so long with the carburetor not emptied, there is a chance it might have nee clogged by the old gasoline. Fixing this problem is easy. Shut off the fuel valve and open the carburetor drain under the carburetor bowl.


If the drain isn’t working, remove the entire bowl from the carburetor bottom and clean it off the stale fuel. It’s also best if you clean out the main carburetor jet – the brass nozzle in the central system using a needle.  


And to avoid this issue in the future, it’s best you run the generator one in a month. Also, avoid storing it for extended periods without draining the fuel of the tank and carburetor.


9) Faulty air filter


Another problem that may be causing your generator not to start is a faulty air filter. The air filter is responsible for cleaning the air that goes to the carburetor for the ignition. You need to clean it or replace it if need be. For that, you have to open the air filter housing on the generator side and the spongy thing inside it. Clean it or replace it with a new air filter if it’s too dirty.


10) Plugged electronics during startup


When you leave connected devices during startup, they tend to drain the battery and make it difficult for the generator engine to start with all the load. If your generator won’t start, and you have electronics plugged in, remove them and try again. That includes the vacant extension cords. Keep all the outlets vacant until the engine starts and normalizes.


11) Cold Weather Problems


It might come as a surprise, but did you know it is difficult to start some cold-weather generators? The battery might get cold and stop functioning, or the weather might be too cold that it’s freezing the gas, which is never good. What you need here is a cold-weather kit for your model to help you deal with this problem. It will help start your generator in the cold weather. You should also try and keep the generator away from the falling snow.


Final Verdict!


These are the most common, easy-to-solve problems that might be causing your generator not to start. Of course, other issues like a faulty engine might also be the issue, but the above can the most common of all. I hope with this list; you won’t be panicking or worrying too much next time your generator won’t start.

About the author

Sharif Miah

I am Sharif, 22, a student, currently doing the BBA program. Besides, I am an online Blogger.

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