The set-up of your go-kart is extremely important for it to run properly, but keeping it in perfect condition can get a little bit complicated. Small things like an old fuel line or spark plug can quickly have a large effect on your go-kart’s performance, and may be why your go-kart is backfiring.
The most common reason for your go-kart to be backfiring is due to the incorrect mixture of fuel and air in the combustion chamber. This means that you will need to change some of your engine settings in order to solve the problem. Backfiring go-kart engines is quite a common problem.
There are ways to fix this issue if you can identify which factor is contributing to your go-kart’s engine backfiring. It takes a lot of patience as well as some trial and error, but eventually you will find the fix. Read below to find out what makes a go-kart backfire and how to fix it if it does.
What Causes Go-Kart Backfires?
A go-kart engine backfires because the fuel and air mixture in the combustion chamber is incorrect. A backfiring engine is always a cause for concern in karting. While not necessarily bad for the engine’s reliability and lifespan, it does mean there are performance issues with the engine.
When there is too much air or too much fuel inside the combustion chamber, the engine may backfire. This means the combustion process is not as smooth as it should be, and that is where engine performance is lost. You won’t have good acceleration and your engine will lose power.
Fuel and air are forced into the cylinder where the spark plug ignites the mixture, which in turn moves the piston. When the fuel and air mixture is wrong, the mixture ignites outside of the cylinder, causing a backfire. Each backfire means that less energy is put into moving the piston, causing the loss of engine power.
Fuel Mixture Is Too Lean Or Too Rich
Go-kart engines are extremely sensitive, especially if you are driving a two-stroke kart such as a Rotax. These engines can be especially stubborn when it comes to changes in the weather conditions, no matter how subtle, so backfiring can be a problem.
The slightest change in humidity or air temperature can mean your engine settings are out and can cause your kart to backfire. In this case, the engine could be running too rich or too lean. You need to use a jetting chart or app along with accurate weather results to find the ideal jetting for your kart.
When the engine is running too rich, there is too much fuel flowing into the combustion chamber. This often results in backfiring, as well as the engine bogging down out of slow corners as the carburetor is flooded with fuel. If the engine is running too lean, there is not enough fuel in the combustion chamber, causing the engine to backfire due to a lack of fuel to burn.
Faulty Spark Plugs
Unlike cars, go-kart engines only have one spark plug, so they rely solely on this one spark plug to ignite the fuel and get the engine going. The kart’s engine is also extremely sensitive to this spark plug, and if the conditions are wrong, it could lead to backfiring and a loss of performance from your engine.
The spark plug on your kart’s engine must be in perfect condition. If the spark plug is faulty, you will experience issues such as backfiring, and you may even find that your kart doesn’t start up properly at all.
You can also use the spark plug to check if your engine is running too rich. After the engine has been running, switch it off, and remove the spark plug. If it is damp or wet, it means that there is too much fuel running into the engine and the spark plug is struggling to ignite it properly.
Fuel Pressure Issue
Like any other engine, go-kart engines need fuel to run. One of the most obvious issues that can often be overlooked by driver and go-kart owners is the fuel lines and the fuel filter. Most people want to go straight for the engine and try to adjust some settings.
In some cases, your kart’s engine could be backfiring because of faulty fuel lines or an old fuel filter. If the engine is not getting enough fuel it will backfire, and sometimes the problem doesn’t lie with the jetting and fuel mixture settings.
Over time, the fuel lines on your kart can begin to become brittle and break. This could lead to fuel leaking out of the lines or in some cases form blockages. The fuel filter can also become blocked with debris, which would result in the engine not getting enough fuel. All of these problems can lead to a drop in fuel pressure and backfiring.
Air Flow Issue
The engine needs two main elements in order to run properly. First, it needs something to combust, which is fuel. In order to combust the fuel, air is also needed inside the engine. If the engine does not get enough airflow there will be too much fuel for the spark plug to combust, resulting in backfiring and a drop in performance.
Airflow problems can be caused by the air filter, which is the box at the front of the engine. If this filter is not cleaned often, it could block airflow into the kart’s engine.
How To Fix A Backfiring Go-Kart
When it comes to a backfiring go-kart engine, it’s always best to try to solve the problem as quickly as possible. The main problem is that backfiring causes your kart’s engine to lose performance, which will slow you down overall and cause you to have a sputtering, jerky ride.
However, in some scenarios backfiring could be caused by an underlying issue. For example, if the engine is not getting enough fuel or air, it could mean that your engine has fuel or air filter problems, which ultimately is not good for the engine’s reliability and its lifespan.
If you don’t solve this issue quickly and instead keep pushing through the backfiring problem, you could end up with bigger problems. If backfiring causes more damage to the kart’s engine, you will have to spend even more money on fixing further problems on the kart.
Clean The Carburetor And Fine Tune It
One of the main reasons for backfiring on a go-kart is to do with the carburetor. The carburetor sends fuel into the engine, and this system ultimately controls how much fuel and air is pushed into the combustion chamber to be fired.
Oftentimes drivers and go-kart owners overlook the importance of cleaning their carburetors. It’s recommended you clean your kart’s carburetor one day before driving the kart. It only takes a few minutes, and it can give you a huge boost to engine performance and reliability. All you need to do is take all the parts off and spray them with carb cleaner, leave them to dry, then put it all back together.
The other issue with the carburetor is the settings that need to be fine-tuned. The jetting and fuel mixture settings on a kart’s engine are extremely sensitive to weather conditions. You need to make use of a jetting chart, or a jetting app (an app will be much more user friendly and easier to use).
If you want to get the best out of your kart’s engine, invest in a portable weather station. These aren’t expensive and they’ll give you a direct reading on the spot rather than having to rely on the weather conditions supplied by your phone.
Replace Spark Plugs
Spark plugs play an important role in the combustion process of a kart’s engine, and ultimately, if you’re experiencing backfiring in your kart, it could be that the spark plug is faulty or worn out. It’s always a good idea to keep spare spark plugs in your toolbox, as they need to be replaced often. Also consider cleaning your spark plug with a steel brush at least once a week if you drive often.
Kart engines are also extremely sensitive to the type of spark plug you use. It’s always a good idea to use the best quality spark plug you can find and try to follow the engine manufacturer’s recommendation of which spark plugs to use in terms of the type and the brand. Don’t go for cheap spark plugs because you’ll need to replace them more often.
Check The Fuel Lines And Filter
The fuel lines on a go-kart are made from cheap material in order to save costs. They’re also exposed to the elements, which damage them over time. The fuel lines are important, and you should always keep an eye on them. There’s no way to maintain them and prolong their lifespan once they become old and brittle, so it’s best to replace them as soon as you can to prevent performance loss.
The fuel filter, just like the fuel lines, is also exposed to the elements and, over time, the fuel filter can become blocked since its job is to clean the fuel of any debris heading into the engine. You should regularly remove the fuel filter and clean it out.
Maintain The Air Filter
The air filter on a kart does an important job. Because the air filter is enclosed inside a box (known as the air box), it can often be overlooked by kart owners. You don’t see the air filter so you may not realize just how dirty it can get, and it’s easy to forget to open this box up from time to time and make sure that it’s clean.
When you’re driving your kart, the air filter is used to prevent any junk from being thrown into the engine. This can range from small pebbles kicked up by the kart ahead, to dust from the track, or even grass off the track. If you don’t clean your air filter often enough, it becomes blocked, preventing airflow into the engine and causing backfiring.
All you need to do is remove the airbox from the engine, open it up, and take the filter out (the filter is the large sponge inside the box). You’ll want to clean out any dirt inside the air box and let the air filter air out as well. You can also replace the air filter if needed as they aren’t usually too expensive.
Backfiring in a go-kart is caused by an unbalanced ratio of fuel to air. Engines need both in the proper proportions to run efficiently and offer maximum performance. Backfiring in a go-kart can be caused by too much or too little fuel, clogged air filters and fuel lines, or bad spark plugs.
I created and have been writing on this site since 2019, collaborating with drivers, coaches, engineers and manufacturers to provide you with the most reliable information about motorsport. Find out more about me here.