ATV Riding

Why Does My ATV Only Run With the Choke On?

Why Does My ATV Only Run With the Choke On?

Running an all-terrain vehicle is a facility and fun on the unusual paths. But, sometimes having ATV, we have to face some unique situations too. Running of ATV only with choke on is among one of those unusual situations.

We are used to on the choke valve while starting our ATV after a long period of no activity or during the cold temperatures. But if we have to on the choke valve every single time before running the ATV, we become frustrated and worried at the same time.

There are two main reasons that make your ATV only Run with the Choke On:

  • Air Leak in Carburetor
  • Cogged Pilot Jet

What is the choke valve in an ATV?

Choke valve is present in every ATV containing a carburetor. The carburetor mixes air with the fuel. The engine of ATV does not solely take in pure petrol. A fixed ratio of air is mixed in the fuel, to increase the rate of combustion as we have already read in our popular science books that oxygen promotes burning.

Choke is pulling lever attached with the carburetor. When we on the choke, it kind of chokes the air pathway in the carburetor. It leads to the production of petrol rich fuel or a fuel having a comparatively very less amount of air in it.

Restriction of air entry in the carburetor reduces the pressure inside it, and thus, comparatively more quantity of fuel enters the engine. It causes the rapid warming of the engine.

When the engine gets warm enough, we again pull the choke lever to its original position. It will still allow the flow of air through the carburetor and provide more clean and efficient fuel to the engine.

Why Does My ATV Only Run With the Choke On?

In this article, our editors have explained common reasons that make your ATV only run with the choke on. 

It is ok to have the choke on to aid bike in starting in winter conditions. But running of bike only with choke on is leading towards some fault in the ATV. Let us explore the possible reasons behind this problem and their possible solutions.

Air leak in the carburetor can make your ATV only run with the choke on

The choke valve was controlling the airflow in the carburetor. So here comes our first suspect, the carburetor.

Air leak in carburetor occurs between the cylinder head and slide of the carburetor. It causes the mixing of more proportion of air into the fuel-air mixture and ultimately results in less efficiency of the engine.

You might be wondering where precisely the carburetor of your ATV starts leaking? Well, the most vulnerable part is the rubber boot of the carburetor. Due to physical pressure on these rubbers, they tend to wear and tear with time.

The wear and tear in these boots can sometimes be challenging to find. You may find the outer part of these rubbers completely fine, but on checking the inner side, you may find a lot of degeneration. You can also be trying stretching these boots to check for any hidden crack in them.

Your ATV is running only on choke, and you are suspecting that problem is might in the carburetor. But how can you have the exact idea that either your suspect is the real culprit or not? Do not worry. We can help you with this matter.

Every carburetor leaking air gives some noticeable indications. Let us go through all of them.

Production of noise:

What can be a more striking and clear symptom than the creation of strange voices from your ATV?

Have you ever heard the sound of gases leaking from a cylinder? Or even gas leaking from a tiny hole in the balloon? If yes, then you must be aware of the hissing sound of the wind.

The simple phenomenon is that when air has to pass through a small hole or a restricted area, then its pressure increases. This increased pressure produces loud sounds.

The same is the case in the leaking carburetor of your ATV. When a small hole is produced in it, then air passes through it, producing hiss sound. Now depending on the size of the breach, this hissing sound could be detected from different distances.

Engine stops on acceleration:

Another noticeable symptom of air leak in the carburetor is the stopping of the engine on trying to accelerate the ATV.

The reason behind this is that the more we accelerate the ATV, the more the fuel and air are allowed to enter the engine. The already leaking carburetor will add an enormous amount of air into the combustion chamber. It will not provide the engine enough fuel to start, and as a result, the engine will miss or stop.

Inconsistent idle:

Here comes the third symptom of a leaking carburetor, the inconsistent idle of the ATV.

You must be familiar with the term idle. You must have kept your engine on while keeping the bike stationary. But in case of a leaking carburetor, the idle is no fun anymore.

Park you ATV. Run it on idle. You will notice an inconsistent idle if your carburetor is leaking. The reason is that leaking carburetor is allowing an unusual amount of air mixing in the fuel. It will further cause the non-burning of the fuel due to the unavailability of enough fuel in the air-fuel mixture.

This condition will lead to an inconsistent idle. Your engine will keep on missing, making idle abrupt and inconstant. You will be no-more be able to control the idle of your ATV.

Loss of engine efficiency:

Last but not least, you will notice a loss of engine efficiency of your ATV in case of a carburetor leak. Highly air enriched fuel will result in total loss of fuel consumption efficiency of the engine. More fuel will be consumed and wasted due to it, and still, you will not get a smooth running of your ATV.

Have you tried very hard with the symptoms but still finding it hard to blame the carburetor for running of your ATV on choke only? Do not worry. We have a simple diagnostic procedure for you to identify carburetor leak in your ATV.

Buy a vacuum gauge meter. Connect it with the tube from the carburetor of your ATV. Lt the reading of the meter stabilizes. When it stabilizes, spray acetone on the suspected parts of carburetor. When you spray acetone on some area, and meter shows an abrupt increase in reading, you have found the leak.

Fix Leak Carburetor in your ATV

So you have finally found the leak in your carburetor. Do not worry pal. There is a solution to almost every problem.

You have to purchase a right carburetor rebuilt kit for your ATV according to the model of your ATV. Besides this, you will require a screwdriver, wrench, rags, and spray carburetor cleaner.

Now, you have to open the carburetor. Start from air cleaner than fuel line, linkage wires, manifold studs, and bowl. Then remove jets from carburetor.

Being all of the old components removed, now it is time to add some new parts from the rebuilt kit. Replace the component causing trouble. Put the whole assembly back in position.

It will surely solve your issue. Otherwise, you can use some market available chemical solutions to fill the gap in the carburetor.

Clogged pilot jet

If you find that there is no air leak from the carburetor of your ATV, then it must be a clogged pilot jet causing the whole mess.

A pilot jet is a component of the carburetor. It is true to say that it is the most critical component of carburetor. The pilot jet essential function is to handle the fuel-air mixture and provide fuel to different parts of carburetor.

As the air comes from the front of the carburetor, it creates a kind of vacuum in the pilot jet. It results in upward motion of fuel in it. It results in the mixing of fuel and air.

Why pilot jet clogs?

It has got many small orifices and passages in it. The entire problem starts here. You may have noticed earlier in your life that this kind of structure gets blocked by the clogging material easily.

It is handling fuel. Over time this fuel keeps on collecting in the small orifices and passages of this pilot jet. It ultimately results in the partial or complete clogging.

You have your ATV being only running with choke on: this is the most prominent symptom of clogged pilot jet. However, to verify it you can look for following signs in your ATV,

Engine misfiring:

Start your ATV and let it run on idle. If the engine keeps on misfiring, then it is an indication of a clogged pilot jet. A clogged pilot jet will restrict the proper flow of fuel to the combustion chamber and ultimately result in the misfiring of the engine.

Improper acceleration of engine:

Another symptom of a clogged pilot jet is the irregular acceleration pattern of the engine. While running your ATV when you will try to accelerate it, there could be two possibilities in case of a clogged pilot jet. Firstly, the engine will accelerate after some time of accelerating. Secondly, the engine will not accelerate at all.

Both of these symptoms refer to a clogged pilot jet of ATV.

Power loss:

Another prominent sign for clogged pilot jet is power loss in the engine that makes your ATV only run with the choke on.

Engine requires a good mixture of fuel and air to operate correctly. However, a clogged pilot jet will reduce the fuel proportion in it. It will result in a less efficient engine. You will notice that the engine is not developing power even at a higher speed.

You may have a physical inspection of the pilot jet. If you are getting above mentioned symptoms from your ATV, then open its carburetor. Remove the pilot jet from it. See-through one side of it.

If you cannot see clearly through the pilot jet or find any clog in the pilot jet, then it is the time to move towards the solution part.

Fix Clogged pilot jet in ATV

Cannot see through the pilot jet? Do not worry; you will start viewing through it after applying our provided solution. This is a must to fix your ATV that only runs with the choke on.

You will need a carburetor cleaning solvent, some heat source, air compressor, and a wire or some other thin long thing.

Step to step guide:

Here is the step to step guide to the cleaning procedure of the clogged pilot jet that is making your ATV only run with the choke on.

  1. Disassembling carburetor:

Well, the first step of cleaning a clogged pilot jet is surely the disassembly of the carburetor. Pull out wrench and screwdriver from your armory and disassemble the carburetor piece by piece.

  1. Making cleaning solution:

Take your cleaning solvent and then take an equal amount of water. Mix them both well in some available pot. You can have a reactively small bowl. After all, it is not like that you are going to wash full ATV with this solution.

  1. Heating the solution:

No matter how much you mix the cleaning solution, the water will not properly mix with the cleaning solution. You have to heat that solution for some time. When you see that water and cleaning solution have mixed well, take it off from the heating source.

  1. Putting a pilot jet in the warm solution:

Now put the clogged pilot jet in that mild solution of water and cleaning solvent. Do not forget to remove the rubber rings from the pilot jet before putting it in the solution. Otherwise, you may have to purchase a new one.

Keep the pilot jet soaked in this solution for at least eight to eleven minutes.

  1. Rinsing and drying of pilot jet:

After eight to eleven minutes, rake pilot jet out of the solution. Rinse it thoroughly and then leave it for drying completely.

  1. Applying compressed air:

After drying the pilot jet completely, use compressed air through its holes. You should have your pilot jet entirely clog-free. Otherwise, take your long thin thing out and pass through the holes of the pilot jet.

So finally you have solved the problem of your ATV. You can have your choke off, and still, your ATV will ride like a queen on all terrains.

Team –

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