When your ATV has issues that make it challenging to ride and enjoy, it can be very frustrating. Nobody enjoys experiencing mechanical problems with their ATVs. However, when a mechanical issue occurs, it not only cuts back on the amount of fun you get to have outdoors, it also winds up costing you time and money. A sputtering ATV is something we get asked a lot about so we decided to address it.
So, what can you do with a sputtering ATV? There are many reasons why an ATV sputters. The most common reason has to do with a carburetor problem like a tuning issue, vacuum leak, or gas leak. Other sputtering issues can be caused by an ignition issue.
For the combustion chamber to work on an ATV, it needs air, gas, and a spark. As long as you take a close look at the mechanics behind this issue with your ATV, then you should be able to figure out why your ATV is sputtering and then fix it. Below we’ll cover some of the reasons why an ATV will sputter that you should check.
ATVs Sputter due to Carburetor Problems
One of the most common reasons ATVs sputter has to do with carburetor problems. Some ATVs have carburetors, and some have fuel injectors. If you have a fuel injector, you can skip this section. Carburetors have been around for a long time, and they’ve been used on many older machines. Carburetors work great on ATVs because they provide the the correct combination of air and fuel that’s necessary to power up the ATV.
However, carburetors can be finicky, and that’s one of the reasons why we see fuel injectors used more commonly today. If you have an older ATV with a carburetor, you shouldn’t be surprised to experience some problems where it isn’t functioning quite right.
When something goes wrong with an ATV’s carburetor, there are three main things that can cause the ATV to sputter.
- A gas leak
- The carburetor isn’t tuned
- A vacuum leak
If you have the right set of tools, then diagnosing the problem and making the repairs should be relatively easy. We’ll cover how to diagnose and fix these issues below.
#1 Diagnosing and Fixing a Carburetor Gas Leak
If your carburetor has a gas leak, the engine will be starved for gas, and that’s why your ATV will sputter when you turn it on. If your carburetor has a gas leak, it was probably caused by a gasket that became brittle or cracked. The gasket you want to look at is located right above the float bowl, which is at the bottom of your carburetor. To see if this is the reason why your ATV is sputtering, pay attention to the smell of gas around your ATV.
You may need to replace your float bowl gasket if you notice that your ATV is sputtering because of a gas leak. Luckily, float bowl gaskets aren’t expensive (you will need to find your model, but here are some general prices on Amazon for different models). Plus, many online tutorials guide you through replacing a float bowl gasket on an ATV depending on what carburetor you have so that should make this fix pretty easy (You’ll need to search for that information based on your ATV’s carburetor, and then proceed from there).
If your ATV has more than one carburetor, you should change each float bowl gasket you have. Chances are if you need to replace one, then all of your float bowl gaskets are probably worn out and failing or close to failing.
Diagnosing should be pretty easy as you should notice the smell of gas if your ATV is leaking gas, you may even visually see the gas leaking. Do a complete visual inspection of your ATV as well so that you can assess where the leaks are coming from. By doing this you’ll be able to see what parts need to be replaced.
#2 Tuning Your Carburetor to fix a Sputtering ATV
Another reason why your ATV might be sputtering is that your carburetor needs tuning. When your ATV’s carburetor isn’t adjusted correctly, then the air screw and fuel screw’s balance between your carburetors are out of line. Whenever that happens, you’ll need to readjust your carburetor.
If you discover you need to retune your carburetor, then we suggest you take it into a shop and have your ATV tuned there. Most people don’t have all of the proper tools for this in their home garage. A mechanic’s shop will have the tools required to fix your ATV, and they can quickly tune it up for around fifty dollars.
So, getting your carburetor tuned at a mechanic’s shop is easy and affordable and easily makes it worth doing. If you had the tools and skills to do this, you probably wouldn’t need our advice anyway. Once your ATV is tuned again, the sputtering should stop, and you’ll get lots more riding time without sputtering hopefully.
#3 Sputtering ATV caused by a Vacuum Leak
If your ATV is sputtering and you couldn’t find a gas leak and a carburetor tune up wasn’t the answer, then you may have a vacuum leak somewhere on your carburetor. Vacuum leaks create many functionality issues in your ATV, and sputtering is one of them. If your carburetor has a vacuum leak, then that means your carburetor isn’t producing the right quantity of air to the air and fuel mixture that makes the engine work. The result of this issue is a lot of sputtering, and it will feel like something is wrong with your engine.
Vacuum leaks occur when the intake boots become cracked or brittle, or when the clamp surrounding them becomes loose between the engine and the carburetor. Fortunately, intake boots are cheap (you can see where yours ranges on Amazon). If the intake boot is causing the sputtering problem, it is an easy fix that you can replace in your garage for a small price.
If it isn’t the intake boot and you still think you are dealing with a vacuum leak, it could also be caused by unplugged vacuum ports that aren’t used. Some carburetors come with many vacuum ports in case someone wants to customize their ATV. However, most people don’t ever use these additional vacuum ports and never customize their ATVs. If you need to replace some vacuum port plugs, then know that this is an easy and affordable fix.
Sputtering ATV caused by Ignition Issues
Carburetor problems aren’t the only reasons why your ATV may start sputtering. If your carburetor is working fine or you have a fuel injector, then your ignition might be what’s causing your ATV to sputter. If your ignition is the problem, you’ll need to look at the following items:
- The spark plugs
- The ignition coil
- The spark plug wires
#1 Check Your Spark Plugs if you have a Sputtering ATV
Start by removing your spark plugs and looking around to make sure you don’t see any corrosion affecting your ATV. Ensure that your point isn’t worn out, and also check to make sure that the gap between your ground electrode and the center looks correct. If you see any issues with any of the spark plugs, pick up a new one for about $10 and swap it.
#2 Check Spark Plug Wires if you have a Sputtering ATV
Some older ATVs have problems with spark plug wires that connect to the spark plug. So if your spark plugs look good, that’s the next thing you’ll need to check. You will want to look to make sure the connection head is correctly attached to the spark plug wire, and that it hasn’t become corroded over time and use.
If you need to replace your spark plug wires, you can pull them apart and un-thread them. You can also clean the wires up, snip them, and rethread them to reconnect the spark plug wires. You should also look for cracks as you check your spark plug wires. If you find any cracks, then they will arc to your ATV’s frame and not through the spark plug. That means your cylinder will wind up misfiring. So, if you notice any cracks in your wires, you’ll need to replace them.
#3 Check the Ignition Coil if you have a Sputtering ATV
Another reason why your ATV may be sputtering is because of the ignition coil. If the ignition coil doesn’t send enough of a spark into the spark plugs, then your ATV will misfire and sputter. If you suspect that your ignition coil isn’t working correctly, then you may need to take your ATV to a mechanic. That’s because ignition coils have high voltages and can be dangerous to handle if you don’t know what you are doing.
A sputtering ATV is annoying, but it isn’t the end of the world. The fix is usually pretty easy and relatively cheap. Even if you have to take it to a shop, it won’t be that bad and you should be back to a fine running quad in no time.