Why Is My ATV Backfiring? How to Fix It?

Whether you call it an afterburn or a backfire, either way, it’s not good. Your ATV has begun backfiring lately when you start it up, and you’re rightfully concerned. What’s causing the issue and how do you fix it?

ATV backfiring is usually caused by low fuel pressure, a carburetor back-up, ignition issues, air leaks, a delayed engine, or a fuel-air mixture that’s too rich. To fix a backfiring ATV, replace the fuel filters, upgrade your fuel, fix leaks, and–if all else fails–see a mechanic. 

This guide to ATV backfiring will tell you everything you need to know. First, we’ll explain what backfiring is, then delve into why your ATV is doing it. We’ll also present repair solutions and tips for preventing future backfires.

Let’s get started! 

What Does It Mean When an ATV Backfires?

From cars to trucks, ATVs, and everything in between, if a vehicle has an internal combustion engine, it can backfire. 

Backfiring occurs when an internal combustion engine ignites the fuel in the ATV’s exhaust system instead of the combustion chamber. The reason it’s called a backfire is that the internal combustion engine causes an explosion through combustion.

An explosion within your ATV might sound very scary, and it can be, as it’s an audible experience. The sound is often described as a loud pop. 

Around the same time you hear this telltale pop, your ATV’s engine may falter for a moment. In some cases, it fails altogether. This is because in the brief moment that backfiring occurs, the engine lacks the proper amount of fuel.

Usually, if backfiring shuts the engine down, restarting your ATV is enough to get the vehicle up and running again. 

The real problem is if you then turn your ATV on only for it to backfire again, and then maybe yet again for a third time. That’s indicative of some sort of issue, whereas occasional backfiring is usually nothing to worry about. 

Why Is My ATV Backfiring?

Now that you understand a little bit more about what backfiring is, it’s time to investigate what might be going on with your ATV to cause such persistent backfiring. Per the intro, here are some backfiring causes to be on the lookout for. 

Low Fuel Pressure

When your ATV doesn’t get enough fuel pressure, then that prohibits the amount of fuel that can reach the engine from the combustion chamber. When the engine is underfed fuel, backfiring will result.

If not low fuel pressure, then a weak, damaged, or old fuel pump could be contributing to the frequency of your ATV backfiring. 

Backed-up Carburetor

Your ATV’s carburetor serves the same purpose as the carburetor in the car or truck you drive. The carb combines fuel and air in an internal combustion engine to produce the proper air-fuel ratio. 

So what causes the carb to get backed up, you ask? Usually, this is due to ATV inactivity. 

Let’s say you skip a season of riding or two because you had work responsibilities, family responsibilities, or any other life issues on your plate. 

For all the time your ATV sits idly, the fuel that’s left in its tank begins to go bad. The quality is much less than what it was the last time you fueled up. 

Then that glorious day happens when you return to your ATV, rev up the engine, and hit the open road. Well, except the low-quality fuel that’s still in the tank travels to the carburetor and gunks it up.

The engine can’t receive the fresh air intake it needs, which interrupts the air-fuel ratio. With more fuel than air, the combustion chamber will begin backfiring. 

Ignition Issues

As we said before, it’s sort of scary when your ATV backfires, as the explosion leads to a popping sound. The popping can be loud, but it shouldn’t be overly loud.

If you hear very noisy, sporadic pops when your ATV backfires and your vehicle happens to experience a loss in power at the same time, then it’s more than likely your ignition that’s to blame. 

Something is wrong with it, and that’s typically up to a mechanic to diagnose. 

Air Leaks

If something inside your ATV is leaking, you know what happens. The air-fuel ratio is again destroyed, as yet again, your vehicle is getting a lot more fuel than air. 

We recommend starting with the header pipes and mufflers as you check for leaks, as those are two areas where leaks are common. 

Engine Delays

The issue could also lie in your engine and its timing. 

The cylinder head of your ATV engine could fall out of sync with the exhaust, which controls the intake compression power. 

The two are supposed to move in conjunction with one another. Delays in their syncing make your engine ignite later than it should.

The exhaust valve will open, and the fuel mixture will ignite then. Your ATV will begin backfiring as a result. This is among the most common ATV backfiring issues. 

Rich Fuel-Air Mixture 

Although a rich fuel-air mixture might sound like a good thing, it’s usually anything but.

The combustion chamber can’t burn all the rich fuel. The fuel that isn’t burned remains in the exhaust system. Once your ATV’s exhaust valve is in the open position and the spark plugs activate, the remaining fuel will begin to burn.

The popping sound you hear will be especially noisy. 

How to Fix a Backfiring ATV

Thanks to the information in the last section, you should be one step closer to determining what’s wrong with your ATV. 

If you’re a handy DIY type of person, then you may be ready to tackle the repairs for your vehicle. Here are your options.

Clean Your Carburetor

To remove the backed-up fuel in your carb, you can clean it yourself. This will allow you to reach the carburetor jets, which are probably filthy as well. 

Look for a slide, cable, and cap on the carburetor. Remove the screws holding these parts together and disassemble the series of hoses attached to the carb as well. 

If your ATV’s gas tank has a gas petcock, make sure that’s in the off position. Then you can safely disconnect the fuel line from the carburetor. 

Take out the fuel overflow line as well and your carb is safe to remove.

Most carburetors will have a carb bowl. You can disassemble this by flipping the carburetor upside down, finding the carb bowl’s bottom nut, and using a screwdriver to unscrew the nut. 

When cleaning the carburetor parts, we recommend a carb cleaner such as Gumout. Use a gentle scrubbing tool to remove gas residue from the carb bowl and other components. 

Then you can reattach everything and try your ATV. The carb cleaner should eliminate or lessen instances of backfiring. 

Here’s a good youtube video to help walk you through the process.

Replace the Fuel and Air Filters

Most ATV models use a mesh filter for the carburetor. The filter is reusable but can get dingy the longer it sits in your vehicle. If you haven’t ever taken out the fuel filter and cleaned it, then please do so now.

How you access the fuel filter varies according to your ATV model. Be sure to check your owner’s manual for instructions. If the owner’s manual doesn’t make it clear, then contact your ATV manufacturer for more information.

Your ATV likewise has an air filter. This looks sort of like the pleated air filters you’ll find in most air conditioning units, and it serves basically the same purpose. Your ATV’s air filter catches contaminants so the air that reaches the engine is clean. 

Most of the time, you can’t reuse an ATV air filter, so you’ll have no choice but to change the filter out periodically. 

Toggle the Throttle Settings

This next one isn’t a fix per se but can still take care of some ATV backfiring issues. If you don’t know how to properly adjust your ATV’s throttle, then it’s possible your engine isn’t receiving enough fuel when in an idle state.

We recommend turning on your ATV, letting it sit idly, and playing with the throttle settings. You don’t need to do heavy-duty adjustments here. Go slow and subtle to see what kind of fine-tuning makes a difference. 

Use a Fuel Injector Cleaner

Besides carburetor cleaner, we also recommend investing in a fuel injector cleaner such as 104+. Designed for carburetor engines, port injection, and more, this product will clean all the components of your ATV’s fuel system.  

See a Mechanic

What if you tried some of the suggestions above but nothing worked? Unfortunately, sometimes that does happen.

More than likely, the issue with your ATV is quite severe. The best course of action at this point is to have a professional mechanic look at it. 

How to Prevent ATV Backfires – Our Top Tips

As we made clear before, ATV backfiring is okay if it’s an infrequent occurrence, but it should not be an everyday part of owning and riding an ATV. 

These tips, when used in conjunction with the information to this point, will help make frequent backfiring a thing of the past.

Keep Your ATV Parts Clean

From the carburetor to the fuel lines, the plugs, and the fuel injectors, clean parts are happy parts because they can work unobstructed. 

Get into a regular cleaning routine, taking the time to go through each component and assess them maybe once or twice a year if you use your ATV regularly. 

Change Your Filters

This goes back to what we talked about in the last section. Filters don’t last forever, and when they’re grimy and coated in junk, they stop working efficiently. 

It takes a few minutes to replace a filter or clean one and re-insert it, yet it can make such a big difference in how well your ATV runs. 

Upgrade Your Fuel

This is another simple change that can prevent ATV backfiring. When you only fill your vehicle with high-quality fuel, then less debris can accumulate in the fuel system when your ATV is inactive.

You might spend more money each time you fuel up your ATV, but in the long run, you’re saving dough. You won’t have to pay for nearly as many costly ATV repairs, after all! 

Final Thoughts 

Your ATV can backfire for a multitude of reasons, but the two most common ones are a rich fuel-air mixture and engine delays. If your carburetor is backed up, air is leaking, or the filters in your ATV are dirty, these issues can also increase the rate of backfiring. 

Whether your choose to fix your ATV’s backfiring issue yourself or take your vehicle to a mechanic, backfiring does not have to be a regular part of using your ATV! 

Geoff Southworth

I am a California native and I enjoy all the outdoors has to offer. My latest adventures have been taking the family camping, hiking and surfing.

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