How To Get An ATV That Has Been Sitting To Run Again


If you have an old ATV that has been sitting for years, it can be difficult to decide what you need to do to get it running again. Let this article act as a guide for you to follow to get your machine out on the trail again.

After a quad has been sitting for a while the oil in the engine, and the gas in the tank will start to separate. Your tires will go flat, and the battery will die. If it’s been sitting out in the weather, you could have worse problems like rust and corrosion.

Here’s a quick list of the things you should be looking to check on. And then I will go into more detail about each, and how to get your ATV running again.

To Get An Old ATV Running Again

  • Drain And Clean The Fuel Tank
  • Clean The Carburetor
  • Change The Air Filter
  • Change The Oil
  • Change The Spark Plugs
  • Change Differential Fluid (4X4)
  • Charge Or Replace Battery

Assuming your ATV doesn’t look like this one below, these steps should get you up and running again. If not, I have some trouble shooting steps to follow later on. But first, lets go over these steps in more detail.

Drain And Clean The Fuel Tank

If the ATV has been sitting for more than 6 months, you will need to get fresh gas in it. Over time fuel will degrade, become less combustible, and start to gum up. Also, water can condense and collect inside a fuel tank that has been sitting for too long, especially fuel with ethanol in it.

It’s best to drain the gas tank completely and clean out any gelled or gummed up gas. This gel like gas residue could also be affecting your fuel lines and other parts in your ATVs fuel system.

Check the fuel filter, and replace it or clean it out if you have to. Also make sure the petcock valve or fuel on/off valves are all working properly. Turn them to make sure they move nicely and aren’t leaking.

If you have a metal fuel tank, the water condensation over time may have rusted out the inside of the fuel tank. I have had good luck emptying the tank and putting a little diesel gas and some small metal BB’s in the tank and shaking it around. The metal BB’s will knock off most of the rust from the inside the tank with the help of the diesel fuel.

Clean The Carburetor

If your ATV has a carburetor, you will want to clean that out completely. You may want to just get a carburetor rebuild kit since you will have the carb already taken apart. Just spraying some carb cleaner in there may not be enough, you will probably need a rebuild kit.

They are pretty cheap and it’s recommended you rebuild the carburetor on a quad that has been sitting anyway. Here’s the link to a Carburetor Repair And Rebuild Kit on Amazon to give you an idea of you can expect to pay.

Check the fuel line coming from the tank and going to the carb. If you can get fuel to flow through the fuel line, then great. If you don’t have a nice continuous flow of fuel, will will need to clean out or replace the fuel lines.

If you are still having problems with the fuel system on the machine, check out this ATV Not Getting Fuel, Common Reasons And How To Fix article where I go into a lot more detail about the fuel system. But if you can at least clean the tank and the carburetor, you’ll probably be fine.

Change The Air Filter

If the air filter is in pretty good shape you might be able to re-use it. But for the most part, I would say it’s best to just replace the air filter altogether. Unless you have one of the re-usable type air filters like a K&N.

Getting a new air filter isn’t going to brake the bank, I recommend just replacing it. But if you do want to try salvaging the existing air filter, or you want to clean a re-usable air filter, check out my How To Clean The Air Filter On An ATV article, where I go through step by step how to get your existing air filter up to snuff on your machine.

Either way you need to make sure the engine is not going to be pulling in dirt, dust, or debris through the air intake. Even small amounts of sand can scratch the cylinder walls and cause you major problems with the engine. Since most ATVs that have been sitting tend to have dust, sand, and dirt collected, you have to sort out the air filter.

Change The Oil

The oil in the engine will usually take longer to go bad than the fuel in the gas tank will, but the additives in the oil will eventually degrade over time. Since you’re supposed to regularly change the oil in the engine anyway, it’s a good idea to do an oil change before trying to start an ATV that has been sitting.

I suggest trying a synthetic blend or a full synthetic oil like this Castrol Power1 10W-40 Full Synthetic 4-Stroke Motor Oil. The reason I would choose synthetic oil is because it was made for older engines. The synthetic oil has additives that will help swell your gaskets, which will help prevent leaks and loss of compression in the engine.

Also, change the oil filter. A lot of people over look this simple step. Every time I do an oil change I change the oil filter out too. The filter could be holding gunk and other things that will contaminate your fresh oil change.

This is a good time to make sure the pistons aren’t rusted into place and the engine isn’t seized up. I like to add a little penetrating oil or deep sea foam into the cylinder head and let it sit in there a while. Simply remove the spark plug to spray a little sea foam into the cylinder head through the spark plug hole.

After letting it sit a couple hours (overnight if it’s real bad looking), I will try to turn it over with the spark plugs out to make sure everything moves the way it should. Since this is easiest done with the spark plugs out, lets talk about that next.

Change The Spark Plugs

The spark plugs on the ATV may be fine and not need to be changed. I know I change spark plugs all the time, and on a quad that sat for a while I would change the plugs out. But this step is really about making sure you are getting spark to the engine.

To do a quick check, simply remove the spark plug from the engine, insert it back into the spark plug wire, hold the electrode on the plug close to the engine or frame, and try to start the quad. If you’re seeing spark jump from the electrodes on the spark plug, you’re probably good to go.

If you aren’t getting spark, try a new plug. If still no spark, you should check out my ATV Not Getting Spark, How To Fix article, where I go more in depth about the spark plugs and the electrical system troubleshooting on the ATV. Also, make sure you get the right spark plugs for your year, make, and model and that they are gapped correctly.

Change Differential Fluid (4X4)

This step is only needed for 4X4 ATVs, and even then you may not need to do this. I usually do it just because I’m already changing all the other fluids anyway, so why not. Besides it’s just as easy as doing an oil change.

You will have a front and a rear differential, you’ll want to change the oil in both. The important thing for differential oil is to use the one that is recommended for your machine. You’ll have to look through your service manual or call the dealer to find out.

There are a few different types and different manufacturers recommend using different oils. Using the wrong one might cause damage to your differential. Once you have the right diff oil, all you need is some socket wrenches and a drain pan.

There will be a drain plug and an inspection plug for both front and rear differentials. First remove the drain plug and let all the diff oil drain. If you notice metal shavings in the oil, you could have a gearing problem. If you notice water or mud in the oil, you may have problem with the seals.

Once the oil has drained put the drain plug back in and remove the inspection plug. This is where you fill the differential with new diff oil. If the oil bottle doesn’t have a fill spout, you may need a funnel for this part.

Fill the differential with oil until it starts coming out of the inspection hole. Let it drain out until it is barely trickling, then replace the inspection plug. That’s it, follow those steps for both front and rear and you should be good to go.

Charge Or Replace Battery

Depending on how long the ATV has been sitting, you may be able to use the existing battery, it will just need to be charged. But if it sat for anything over a year, you’ll probably need to replace the battery all together.

If you need some tips on what charger to use or how to charge an ATV battery, check out my How To Charge An ATV Battery article. But most likely, this won’t help you all that much and you’ll end up needing to get a new battery.

You can usually get an ATV battery at your local auto parts store or at an ATV dealer. But I’ve been able to get batteries online for cheaper than they charge in the store. If you can wait for shipping, just get an ATV Battery On Amazon.

Try To Start It Up

Alright, you’ve done the tune up, now it’s time to try starting up the ATV. Put some fresh fuel in the tank, make sure the kill switch is on run, the key is on, and give it a go.

ATVs that have been sitting may be a little harder to start, especially older models. Give it some time and be patient, but not so much that you kill the battery trying to start it.

If you do get it running, I suggest putting some fuel system cleaner in with the gas and letting it run with that in it for a little bit. That way it can really clean out the rest of the engine. I use this Gumout Complete Fuel System Cleaner in my quads about once a year, and it works great.

Troubleshooting, Still Doesn’t Run

If you still can’t get the ATV running, you may have bigger problems you need to dive into. Most likely you have a problem with spark, fuel, or compression. Those are the most common reasons an ATV fails to start up.

To get more in depth step by step instruction to troubleshoot why your ATV still won’t start up, check out my ATV Won’t Start, Common Problems And How To Fix article. That article will solve 90 percent of the reasons an ATV won’t start.

Rob

That's me sinking another ATV. I love to ride no matter what it is, snowmobiles, four wheelers, dirt bikes, and anything else off-roading. I've experienced my fair share of machines, and like to share that experience here.

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