Go-karts are some of the simplest and most primitive vehicles you can find. However, karts have developed over time and there have been some more complex elements added to them in order to improve performance and reliability. One of these elements is a fuel pump.
Go-karts do need fuel pumps. These are necessary as the fuel tank is situated relatively far from the engine and is also found lower down on the chassis. This means that fuel needs to be pushed into the engine through the use of a pump.
Despite that, the fuel pump on a go-kart is extremely simple. It can be replaced with relative ease and in little time. Fuel pumps are essential parts of a kart engine, and below we’ll give you more information about go-kart fuel pumps, and how you can replace one.
Why Do Go-Karts Need Fuel Pumps?
Many people have speculated that go-karts use different ways to feed fuel into the engine because of the fact that they are so primitive and cheap to maintain. A fuel pump is a relatively complex element to add on to such a small and simplistic engine.
Other forms of feeding fuel into the engine involve gravity or fuel siphoning systems.Go-karts are unable to use these systems because they require the fuel tank to be above the engine. The gravity feed system requires fuel to run down into the engine from above, which isn’t possible on a kart.
Go-karts have their fuel tanks at the front of the kart, between the driver’s legs and underneath the steering wheel. This has been done for a number of reasons. Firstly, the size of the tank makes it an awkward part to place anywhere else on the kart. There is no space anywhere closer to the engine.
Secondly, due to the open nature of a go-kart, the fuel tank cannot be placed anywhere else. Any other location will leave the fuel tank too exposed. In the result of an accident, a punctured or dislodged fuel tank could end in disaster.
The Factor Of Weight
Fuel tanks are also placed in their specific location due to their weight. When the kart is loaded up with fuel, the fuel tank can become the third heaviest element on the kart after the driver and the engine.
Weight makes a massive difference when it comes to karting, and therefore the placement of the fuel tank is critical. Placing it underneath the driver is the best location to keep the kart’s weight as balanced as possible.
Go-karts need fuel pumps in order to feed the fuel back to the engine. It is quite a long distance for the fuel to flow from the tank, in front of the driver to the engine, which is located behind the driver.
Nevertheless, fuel pumps found on go-karts are small and relatively simplistic. The fuel pump can be found as a small rectangular box underneath the carburetor. It is attached to the metallic support bracket.
It is operated by pulling power from the solenoid. The solenoid pulls extra power from the engine crankcase in order to run the fuel pump. But what happens when there’s a problem with your fuel pump?
How To Identify A Faulty Fuel Pump
A failing fuel pump can be a disaster for your go-kart. Not only will it affect your performance, but it could also end up damaging your engine if you run a faulty fuel pump in the long run. It’s important to keep an eye out for these indications.
Many of these symptoms can also be related to other problems so it’s important to find the solution swiftly. In some cases, it could have similar symptoms as running the wrong jetting, overdriving your kart or having an incorrect air to fuel ratio.
Engine Sputtering At High Speeds
You might find that your engine is sputtering or backfiring at high speeds on the straights. This could simply be due to you using the incorrect jetting or having your fuel mix too lean. However, if you are sure that those engine settings are correct, it could be an issue with your fuel pump.
High Engine Temperatures
If there is an issue with your fuel pump you may experience higher engine temperatures. You can easily monitor your engine temperature using a Mychron device. Excessive engine temperatures could also be caused by high ambient temperatures, a radiator issue, or an air filter issue.
Loss Of Power
You may be experiencing a lack of pull out of slower corners. Almost as if the kart is bogging down. This could be down to your engine not getting sufficient amounts of fuel to burn if the fuel pump is faulty. However, another cause could be from running your fuel mix too rich.
Engine Not Starting Or Idling
If your engine is not starting, it is clearly a sign that something is not right. Although there may be many causes for an issue such as this one, the fuel pump may be one of them. Do a quick check on the line that runs from the engine crankcase to the fuel pump. If this line is not connected properly, the engine will not start.
On the other hand, if your kart struggles to idle and the engine tends to cut out when you don’t touch the throttle, it could also mean there is a faulty fuel pump. In some cases, it could also be the clutch shoes that need to be replaced. You should always ensure that your clutch is properly maintained.
Air In Fuel System
If your kart engine is running and you see air bubbles in the fuel line, it could be a sign that your fuel pump is on its way out. Be sure to check your carburetor to make sure your engine settings are correct before replacing your fuel pump.
Tools You Need To Replace A Kart’s Fuel Pump
Replacing a fuel pump is relatively simple process, and it can be done quickly. It’s best to do this job with the engine removed from the chassis. It’s not essential, however it can make the process much easier and more comfortable.
A new fuel pump for a Rotax kart engine costs around $70. You can also find aftermarket fuel pumps for half the price if you want to save some money. Make sure you also get the fuel lines and fuel filter, which are not always included.
Here are some tools that you will need to replace your go-kart’s fuel pump:
- Torque wrench
- 5 mm Allen Key
- Long-nose pliers
- Fuel filter
- Fuel pump with bracket
- Additional fuel lines
How To Replace A Fuel Pump In 6 Steps
1. Remove Your Carburetor And The Old Fuel Pump
The first step to installing a kart fuel pump is to remove the carburetor. You can remove it from the engine completely and set it aside. Undo all the fuel lines connected to the pump. Next you will need to undo the bracket you can see underneath the carburetor. The fuel pump is attached to the bottom of this bracket.
2. Attach The New Fuel Pump
Now you should have the old fuel pump off the engine. When you have your new fuel pump ready, set your torque wrench to 6 Nm and tighten the screws found on the bracket to the engine.
3. Attach The Fuel Filter
The next step is to attach the fuel filter to the fuel line. You will notice that there is an arrow on the fuel filter. The arrow is supposed to point towards the fuel pump, in other words towards the engine, not towards the fuel tank. Use the long-nose pliers to stretch the fuel lines open. This makes them easier to attach.
4. Attach The Fuel Lines
Next, you need to attach the three fuel lines to the pump. The shortest line attaches directly to the fuel pump. The black line attaches to the solenoid valve. Finally, the longer clear line attaches to the crankcase.
The long, clear line which attaches to the crankcase is the most important. This line is what powers the solenoid. The solenoid is what charges up the fuel pump. If the crankcase line is not connected properly, the engine will not start. Always make sure that it is connected properly.
5. Connect The Solenoid And Exhaust Valve
The penultimate step is to connect the separate black line from the solenoid valve to the exhaust valve. This allows the solenoid to electronically open the exhaust valve at a specific RPM.
6. Tie Down Loose Lines
When everything is done and properly connected, make sure that you attach all the loose lines with cable ties. This will ensure that the lines are not hanging loosely off the engine in a way that they might get caught or dislodge. However, if you pull the cable ties too tight you might block them, so make sure you don’t do that.
Fuel pumps are crucial parts of a go-kart’s engine. They are needed because of how far away the fuel tank is situated from the engine. When fuel tanks fail, they can cause many problems. Fortunately, replacing a fuel pump can be a quick and easy process if you know what to do!
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.