If your ATV is running rough, or the idle isn't as smooth as it used to be, there's a chance that the carburetor may be to blame. Even if you haven't changed anything, the vibrations from the engine itself can actually cause adjuster screws and cables to shift over time. Luckily, there are a few basic steps you can take to narrow down the source of the problem before you call a mechanic to look at it. Here are some tips to help you find the issue.

Cleaning the Carburetor

Your ATV's idle should be a bit like your car – consistent and smooth. If it's skipping, jerky or rough, you may have a clog in the carburetor. If so, cleaning it out should restore it to its original operation. In most cases, the carburetor is mounted under the ATV seat, at the top of the engine. Remove the seat to expose the engine, and you'll find it.

Have plenty of clean shop rags and a spray carburetor cleaner on hand for this job. When you take the float bowl off the top of the carburetor, make sure that you make a mental note of where the fuel lines connect so that you can reattach it after. You'll just need a small wrench for this part.

Spray the float bowl with the carburetor cleaner and use an old toothbrush or small shop brush to clean the inside of it. Make sure that there's nothing in the jets. Then, wipe it clean with shop rags before your reattach it.

Adjusting the Idle

If you're certain that the carburetor is clean, the idle problems may be due to poor adjustment on the carburetor itself. You may need to adjust the idle to restore the balance. Adjusting the idle simply means altering the ratio of the fuel to air that the carburetor uses when it runs. If there's too much of either one, it can cause the ATV to run rough, because it isn't getting the mixture that it needs. You'll need to experiment a bit with the idle adjustment screw in order to find the precise ratio for your ATV.

Locate the screw on the side of the carburetor body. The farther out the screw is, the more air the engine's getting when it runs. Turn the engine off, then tighten the adjustment screw all the way. Make note of how many turns it needed to tighten it. This tells you how far out to return it if necessary to get it back where you started.

Then, start the engine. Turn the screw out a quarter turn, and keep repeating the turn until the engine speed drops to a smooth idle. Turn the screw back in a quarter turn, repeating the process until the idle increases again. The key is to find the precise location for the adjustment screw where the idle is smooth and even, then you stop turning it.

If the tips presented here don't restore your ATV's natural idle, you may have problems in the fuel system. In that case, you'll need an ATV repair technician like Canyon Honda to help you narrow it down.