How ATV Fuel Pumps Work: Common Issues and Fixes

It’s impossible to run an ATV effectively without a reliable fuel pump. Knowing how they work, their common issues and quick fixes are all necessary.

ATVs run with either a mechanical or electric fuel pump that draws gasoline from the tank, cleans it, and sends it to the engine to create a combustion of some sort. Common ATV fuel pump issues include worn-out seals, wear and tear, and bad filters. Most problems require a total replacement.

After years of dealing with plenty of failed fuel pumps and working closely with technicians, we discovered how they work and the most common issues. This allowed us to learn more about the best fixes too. This guide includes all this information, so keep reading to learn more.

‍How ATV Fuel Pumps Work: Common Issues and Fixes

ATV fuel pumps are vital components of your vehicle’s engine system, responsible for delivering the precise amount of fuel to the carburetor so that it can be mixed with air and burned for power.

At its basic level, an ATV fuel pump is a small electrical device that draws gasoline from the tank into a diaphragm chamber, allowing pressure to build up as excess gas is vented back into the tank.

As this pressure rises, a valve opens, allowing pressurized gas to flow through pipes to the carburetor or injectors. Unfortunately, due to age and general wear-and-tear, ATV fuel pumps can often suffer from premature failure, meaning they no longer work as well as used.

There are also two types of fuel pumps, and they work differently. This includes a mechanical and an electric fuel pump.

Mechanical Fuel Pump

The mechanical fuel pump is essential to any internal combustion engine, ensuring the engine has a sufficient fuel supply. This type of fuel pump uses a diaphragm-activated arm to create suction and move fuel from the tank to the carburetor.

Here’s a look at how a mechanical fuel pump works:

First, it utilizes an inlet valve to draw fuel into its cavity. The amount of fuel drawn in is determined by the pressure difference between the pump and its internal environment.

This inlet valve is connected directly to the engine’s intake manifold, which contains air and gasoline vaporized from liquid gasoline in the carburetor bowl. This pump is much more compact on an ATV than on a traditional vehicle.

It’s located near the gas tank, so it’s easier to siphon fuel from the tank to push through the pump. The air/gasoline mixture flows through this valve into the pump’s cavity, which is forced through a thin diaphragm that activates a lever or arm inside it.

There’s also a filter, so the fuel is clean and doesn't damage the engine. At higher RPMs, more pressure must be built within this system - thus requiring faster action from your mechanical fuel pump.

Electric Fuel Pump

The electric fuel pump also ensures that the right amount of fuel is delivered to the engine to run efficiently. With an electric fuel pump, your ATV can run more lean and rich, resulting in better performance and increased repairs down the road.

The mounting is where the fuel pump sits securely in place on the vehicle. Depending on your ATV, it may be mounted on top of the gas tank or directly into the side/bottom of it.

At least one electrical connector allows power from the vehicle battery to reach the fuel pump motor. A second connector usually attaches a single line from the pump motor to deliver gasoline to other engine parts.

The motor powers up after getting electricity from your battery and turns a drive shaft connected with gears that move and pressurize gasoline using centrifugal force. This causes fuel pressure throughout all parts of an ATV's system needed for combustion.

But the critical difference with this pump is the lack of a camshaft included with a mechanical design. Instead, there is a solenoid that pulls on the diaphragm. This is the crucial function of sending petrol into the chamber to allow for acceleration.

Common ATV Fuel Pump Issues

Riding a four-wheeler can be a fantastic experience. However, it is vital to always take care of the machine that gives you such an experience, including maintaining its fuel pump.

Not doing so could lead to some nasty consequences, including engine failure or severe damage, reduced performance, and unplanned expenses. All these issues can be avoided by knowing what common ATV fuel pump issues can occur and how to spot them early on.

Worn Out Seals & Gaskets

One of the most common ATV fuel pump problems is a leak in the system caused by worn-out seals or rubber components. It can be dangerous and lead to fuel pump failure too.

This kind of leak will cause the vehicle's performance to suffer dramatically as there won't be enough pressure built up in the system for proper combustion inside the engine cylinders. When this happens, there is inefficient power delivery and decreased acceleration capabilities.

Overheating & Wear

ATV overheating and wear and tear can eventually cause a fuel pump to fail. Regular maintenance is a must, as it can prevent some of these problems from occurring in the first place.

Suppose you experience any signs that the fuel pump is failing, such as erratic vehicle operation or loud noise from the engine bay. In that case, it’s best to take your ATV to a service technician as soon as possible so they can identify and repair the issue at hand.

Bad Filters

If the filters are bad, it can result in clogging or a poor filtration process. Clogs within any part of the network between a reservoir and corresponding entry points would prevent sufficient oil content from arriving at motor parts.

They can lead towards the worst nightmare scenario - a complete lack of power generated while attempting the current ride session. This can lead to far more damage than just a faulty fuel pump.

When the filters go bad, it can lead to contamination too. This is one of the primary concerns when maintaining fuel pumps.

Common ATV Fuel Pump Fixes

Common ATV fuel pump fixes include checking the relay, fuse, and other wiring connections. If there is no power to the fuel pump, you may need to replace the ignition switch or check for a blown fuse.

You may also need to inspect the system's electrical components, such as the CDI box and coil, as these can cause problems with fuel delivery. We’ll explain various solutions below worth considering.

Check The Power

First, we recommend checking the power and carburetor to decide what could be wrong with the fuel pump. This is our primary power source, so spraying a little carburetor cleaning could fire up the engine and highlight the issue or repair it for us.

Pouring fuel into the carb is also possible to see if the engine starts up. If it starts and maintains power, we know the carburetor is not getting fuel from the pump.

Replace The Fuel Injectors

One of the easier solutions to fix a malfunctioning fuel pump is replacing the fuel injectors. They can easily get clogged up after extended use, so it’s better to just replace them than try cleaning worn-out ones.

The fuel injector holes need to be clear for the fuel to pass. When clogged, the fuel pump cannot complete the fuel injection process, and the ATV will struggle to start or maintain power because of a lack of gas.

Check The Fuel Line & Pump Flow

Next, we must check the fuel line to ensure the pump works. If there is any air restriction, we clearly have a clogged pump that needs cleaning. The best fix is to blow air through the pump.

But this cannot be done with vacuum-operated fuel pumps because of the diaphragm. Instead, try cranking the engine with the vacuum line disconnected to see if there is any suction. If not, we have a clogged pump that needs cleaning.

Signs An ATV Fuel Pump Is Bad

When an ATV fuel pump goes bad, there are some clear and obvious signs to keep an eye out for that tell us we need a replacement. Unfortunately, they do wear out after enough wear or poor maintenance.

Won’t Start Or Hesitating When Starting

If the ATV won’t start or hesitates when starting, this is a clear sign that either the pump is bad or the fuel line needs to be replaced.

Many people also experience low output or complete pressure loss, resulting in varying engine performance when accelerating or idling. These problems indicate that the pump is old, worn, and no longer working correctly.

Idles Without Revving

If the ATV starts, but the engine only idles without revving, it can also indicate the fuel pump is bad. This is a sign the pump cannot generate enough power, and if any fixes we recommended don’t work, the pump should be replaced.

Hard Cranking

When the engine is hard cranking, it’s a sign the spark plugs, fuel injectors, or fuel pump needs replacing. In most cases, the more severe cranks mean the fuel pump struggles to send fuel to the engine.

The air and fuel mixture has been distributed and contaminated, so the engine can’t run cleanly. We recommend a fuel pump replacement as soon as possible.

Poor Fuel Efficiency

Lastly, poor fuel efficiency indicates the ATV fuel pump is bad. It burns fuel faster despite driving the same distances, and it’s an early signal that more severe issues could be on the horizon if they don’t get replaced soon.

How Do You Replace A Faulty ATV Fuel Pump?

Begin by removing the seat from your ATV. Depending on your model, this may be done using a Phillips head screwdriver or an Allen wrench.

Once the seat is off, you will need to locate and disconnect the fuel line connecting to the pump. This should be at the bottom of your gas tank or close to it.

Grab both sides of the line and disconnect accordingly using a pair of pliers. Now remove any bolts attaching the old pump to its housing before taking out the old pump.

Next, take out your new fuel pump and follow all included instructions carefully to install it properly. Reattach all components firmly before reinstalling your ATV's seat and connecting back up all necessary wiring for power, if applicable.

Finally, test that everything runs properly before taking it out for a spin. If this seems complicated, consider asking a technician for some help.

Recommended Articles

• ATV and UTV Fuel Efficiency: Complete Guide
• How to Treat Your ATV's Fuel
• Electric vs. Gas Powered UTV

Key Takeaways

• The most common issues with ATV fuel pumps are worn-out seals, wear and tear, and bad filters. When these occur, the ATV will hard crank, idle without revving, and lose power.
• We recommend checking the fuel line and injectors for clogging, replacing the injectors, or replacing the fuel pump entirely.