Why Does My Generator Only Run on Choke? Champion, Honda, Yamaha

Generators, specifically smaller generators, are extremely handy appliances. They’re great to power household essentials during power outages, and they’re also great for contractors on construction sites. Small generators are also commonly used in outbuildings such as barns, shops, or RVs to improve your camping experience. One of the most common problems with small generators is that they sometimes only run with the choke turned on. 

If your generator only runs with the choke on, several different issues could be happening. However, the underlying problem is that your engine is getting more air than gasoline. There are four issues that could be causing this to happen, and they all have to do with your carburetor, fuel, or engine. 

What Does the Choke do for a Generator? 

Before you can fix a generator that only runs with the choke on, it’s essential to understand the choke’s purpose. Let’s go over the chain of events that causes your small engine generator to operate. 

The Air and Gas Mixture 

Your generator’s engine runs on a combination of air and gasoline. It contains an intake, a carberator, a piston, and many other components, but these are the three we will focus on. Your intake sucks air in from outside the generator with the aid of the piston. Your piston is like the heartbeat of your engine and moves up and down rapidly, sucking air in and moving air out. 

As this is happening, the air is sweeping through your carburetor at such a high speed that it takes gasoline with it into the engine. The correct mixture of air and gas helps your engine run smoothly and efficiently. 

The Choke 

When you initially start your generator’s engine, it sometimes needs more gas than air to run. This is because your engine isn’t primed yet and is essentially starting from scratch, which is where the choke comes in. The choke is located on the carburetor and acts as a damper that blocks air from entering the carburetor. Remember that it doesn’t completely cut off the airflow. It merely dampens it and minimizes it. 

Because not as much air flows through the carburetor, your engine takes it upon itself to suck air from anywhere it can. As a result, it will suck the air out of the gas tank, which has the effect of drawing pure gasoline into the engine. A higher amount of gas, as opposed to air, is necessary when initially starting your engine to get it lubricated and warmed up. 

What Should Happen

When your engine is running smoothly, you should now be able to turn the choke off. Turning the choke off opens the damper on the carburetor and allows air to flow through it once again. Under regular operation, your engine shouldn’t need pure gasoline anymore and should operate perfectly with the mixture of gas and air produced by the piston. 

However, if there’s an issue with your carburetor or engine, your generator will stall out and turn off when you turn the choke off. This happens because gas is not mixing correctly with air as the piston pulls air into the generator and pushes it out of the exhaust. 

How do you fix a generator that only runs on choke?

If your generator only runs when the choke is off, there’s a problem with your carburetor, engine, or other component. The only way to fix a generator that only runs on choke is to figure out what the problem is and fix it. Let’s go over the list of problems that could be happening and the possible fixes for them. 

1. You Have Bad Fuel or Gasoline 

Many people don’t realize that not all gases are created equal. This is why there are so many different options when you fill your car at the gas station. The concept is similar for generators and other appliances with small engines. If you are using old, dirty, or poor-quality gasoline, there’s a good chance that this is the reason your generator only runs with the choke on. 

This is because once you turn the choke off, your engine isn’t sucking in quite as much gas as it does with the choke on. Because the gas you’re using isn’t as good as it should be, it needs a higher dosage to operate. You should empty your generator of gasoline and refill it with high-quality ethanol free gas. You should also add a fuel stabilizer to the gas tank after you refill it to keep your gas good for longer periods of time. 

You will also need to empty your carburetor, which will also likely be full of gas. 

2. Clogged Main Jet or Emulsion Tube 

The second reason your generator is only running on full choke is that you have a clogged main jet or emulsion tube. Both of these components are located inside the carburetor, and you’ll have to take them apart to access them. However, the more likely culprit is the main jet, so make sure to focus on that component. 

The main jet and emulsion tube essentially vaporize the gasoline as it’s flowing through it in order to better utilize it. If the main jet is clogged, gasoline is unable to pass through, and the result is that your engine will stall when you turn the choke off. With the choke on, enough gasoline is able to make it to the engine to operate. 

Choke problems on generators hold true no matter what brand of generator you have. While higher-end makers such as Generac, Honda, Champion, and Yamaha have fewer problems than lower-end models such as Westinghouse and similar brands, none of them are immune. 

3. A Dirty Pilot Jet 

The issue with the pilot jet is similar to what happens with the main jet and emulsion tube. Gasoline is meant to flow through the pilot jet uninhibited, which means that even a slight blockage will cause issues with your generator when the choke is off. 

Remove the pilot jet and make sure that the tiny hole on the bottom of the jet is clear and obstruction-free. When the choke is off, enough gas flows to the engine to keep it running in spite of a dirty pilot jet. When you turn the choke off, however, the obstruction in the pilot jet is enough to cause your generator to stall and turn off. 

4. Your Carburator is Not Tight, or There’s a Damaged Gasket 

While this problem is rare, it can still happen and cause your generator only to run when the choke is on. Roughly 95% of the time, when your generator only runs with the choke on, it’s because of one of the first three reasons. However, an under-tightened carburetor or a damaged gasket can cause a similar problem in rare situations. 

If your carburetor is loose or has a damaged gasket, it will allow too much air to mix with the engine’s fuel. When this happens, it will cause your generator to stall out and shut down because there isn’t enough fuel in the engine. However, if the choke is turned on, it cuts off airflow and sends a higher supply of fuel into the engine, which is why your generator only runs when the choke is on. 

5. Clogged Fuel Filter or Fuel Line

Gunk from your gas tank can accumulate in the fuel filter or even build up in the gas lines. This will restrict the flow of gasoline to your engine causing it to only run with the choke on. Replacing your fuel filter and fuel lines is cheap and easy to do. This should be done routinely to keep up with your small engine.

Why does my engine only run with the choke on?

The reason your engine is only running with the choke on is that your engine is able to get a higher concentration of gas when the choke is on. Your choke blocks air out of the carburetor, which means that your engine is sucking more gasoline. This is often necessary when cold-starting your engine, but as it warms up, it shouldn’t need pure gasoline to operate. 

Is it OK to run a generator with the choke on?

Running your generator full-time with the choke turned on isn’t a good idea. Under ideal conditions, your generator is meant to operate with a mixture of gasoline and air. Running a generator turned on all the time will cause your generator to use too much fuel and not enough air.

Not only will you burn through fuel and lose money, but you also run the risk of having your carburetor clogged with fuel or of creating a vacuum leak because air isn’t able to pass through the carburetor. 

Why does my small engine only run on half choke?

Your small engine only runs on half choke is the same as the reason it only runs on full choke. There’s an issue with your fuel quality, main jet, pilot jet, or carburetor, causing too much air and not enough fuel to enter your engine. If the engine runs on half choke, the problem isn’t quite as severe as when it only runs on full choke. However, it’s a problem and will progress to a full choke problem if it isn’t fixed. 

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