Coolster 125cc ATV Carburetor: Features, Problems and Maintenance Guide

An off-road quadcopter, the Coolster 125cc ATV has four wheels. Light to medium-duty work is suitable for its 125cc engine, which produces around 8 horsepower. The Coolster 125cc ATV Carburetor is a part of the ATV’s engine that mixes air and fuel to create a combustible mixture that powers the engine.

With a variety of terrain types and operating conditions, these inexpensive behemoths performed reasonably well. A parent’s prayer was answered with the Coolster brand. Its brilliant combination of utility and sport makes the Coolster ATV one of the best on the market.

Now, we will talk about the Coolster 125cc ATV Carburetor.

coolster 125cc atv carburetor
coolster 125cc atv carburetor

What Is a Carburetor?

An internal combustion engine is powered by the combustion of fuel and air by a carburetor. Based on Bernoulli’s principle, it reduces static pressure as air moves faster, thereby increasing dynamic pressure.

Venturis on ATV carburetors allow air to pass through the engine’s inlet manifold, allowing air to enter the carburetor. It is the inlet manifold that supplies the cylinders with air/fuel mixture, also known as the intake manifold.

Airspeed is regulated by strategically widening and narrowing the venturi. There’s a butterfly valve called the throttle valve, which can be turned to either block or allow airflow into the system. In order to regulate engine speed and power, the valve controls the amount of air flowing through the carburetor’s throat.

A venturi usually has small holes on the narrowest part that allow fuel to be introduced. Jets ensure that fuel flow in the fuel path is precisely controlled, allowing proper combustion to take place.

How Does an ATV Carburetor Work?

Different carburetors are usually designed differently and have different levels of complexity. The purpose of most of these mechanical devices is the same: to promote combustion by mixing air and fuel, and thereby to power the engine.

The most common design for ATV carburetors is a simple one. The vertical air pipes are strategically positioned above the engine cylinders. In the venturi, the vertical air pipe is joined to a horizontal fuel pipe (at its narrowest point).

As the air speeds up, its pressure fails, which creates a much-needed sucking effect for the release of fuel. Above and below the venturi of the carburetor are two swiveling valves that regulate the air-fuel mixture.

Venturis use a choke valve to control how much air can flow through them. In an engine with a choke closed, the venturi is allowed to take in more fuel, resulting in a rich mixture of fuel and air.

A cold engine, a slow-running engine, or a newly started engine can greatly benefit from this feature.

The second valve is called the throttle, and it is also used to regulate air-fuel mixtures. The more airflow through the carburetor, the more fuel is sucked, so the more throttle you open, the more fuel you get.

As a result, more energy is released, more power is generated, and eventually a faster ATV is produced, which is why opening the throttle valve accelerates an engine.


Coolster ATV Overview

Doug Stabler of the ATV Wholesale Outlet in California distributes the Coolster ATV in the U.S. ATVs like the Coolster rose to fame in 2006, and they were so popular that the House passed a law (H.R. Bill 4040) preventing foreign three-wheeled ATCs from being manufactured, sold, and imported into the country.

The U.S. market has 14 models with different displacements. Coolster 110cc ATVs are air-cooled, four-stroke mini-sized ATVs. Off-road fun for beginners and younger riders is made easy with robust double a-arms, shock-absorbent suspensions, and easy handling! With its larger displacement, the Coolster 125cc is an easy-to-maneuver 125cc ATV. Full coil-over suspension, big tires, and automatic CVT transmission make the Coolster 150cc ATV stand out. In addition to the extras, it comes in several colors.

Coolster ATVs are affordable, which makes them appealing. There are many model options, and parts are always available. Compared to mainstream parts, replacement parts are much cheaper. When consumers make a purchase, they are assured that they will receive exceptional customer service.

Coolster 125cc ATV Overview

This ATV is a good choice for kids because of its dependable performance and safety features. First of all, the footrest is wide and non-slip, and the bumper is sturdy. The speed controller allows riders to reduce the speed to 5 mph. Located on the dashboard, the kill switch is easily accessible and enables the rider to turn off the engine with just one push. With the kick-start feature and the automatic transmission in reverse, the engine can be started and stopped easily.

Coolster 125cc ATV Parts

It is essential to maintain and replace parts on the Coolster 125cc ATV to ensure optimal performance and longevity.

There are several important Coolster 125cc ATV parts, such as:

Carburetor

As mentioned earlier, the Coolster 125cc ATV carburetor is a crucial component of the engine system that mixes fuel and air to power the vehicle. Poor performance and engine damage can result from a malfunctioning carburetor.

Clutch

An ATV clutch engages and disengages the engine from the transmission as part of the transmission system of a Coolster 125cc ATV. Using it, riders can shift gears and control ATV speed smoothly.

Transmission gears connect the engine to the clutch, which works as a connection between the engine and the transmission. When riders pull in the clutch lever, they can shift gears or bring the ATV to a stop. ATV’s wheels receive power from the engine when the clutch engages, and the transmission transmits it to the transmission. To engage or disengage the Coolster 125cc ATV clutch, the rider must manually operate the clutch lever. Practicing this can help you control the ATV’s speed and power more precisely and effectively.

Spark plug

Coolster 125cc ATV spark plugs ignite the air-fuel mixture in the combustion chamber of the engine through a spark, which creates a spark. An engine’s performance and reliability depend on the spark plug, a tiny but vital part.

Located on the cylinder head, the spark plug is wired to the ignition coil. Electricity is sent through the wire to the spark plug when the engine is running. Spark plug ignition of compressed air-fuel mixtures inside the combustion chamber produces the power to drive the ATV’s wheels.

Air filter

ATV’s Coolster 125cc engine’s air filter filters dust, dirt, and other particles out of air entering the engine to avoid damaging it. By supplying clean air to the engine, the air filter ensures proper combustion and engine performance.

There is usually a metal or plastic box housing the air filter on the top or side of the engine. It traps dirt and debris while allowing clean air through and is usually made of paper or foam.

Clogged air filters reduce engine performance by restricting airflow to the engine. Maintaining a clean air supply to the engine requires regular inspection, cleaning, and replacement of the air filter.

Battery

Battery power is critical to the Coolster 125cc ATV’s electrical system. Electrical components such as light bulbs, starters, and starter motors require electricity to function. A 12-volt sealed lead-acid battery powers the Coolster 125cc ATV. ATV electrical systems are reliable and durable. Coolster 125cc ATV batteries have a sealed design. No maintenance is required, like adding water to the cells or checking electrolyte levels.

Acid leaks can damage vehicles and pose a safety risk to riders due to the sealed design. You can easily replace the Coolster 125cc ATV battery under the seat. Maintaining a healthy battery requires regular checks. You should replace a weak or dead battery.

The Coolster 125cc ATV Carburetor

It is one of the most important components of the Coolster 125cc ATV engine system. Carburetors mix fuel and air to power engines with the right proportions.
Off-road riding will be no problem for this Coolster 125cc ATV Carburetor, which is made from durable materials. As a result, the ATV runs smoothly and efficiently in a variety of terrain conditions.

Adjustable design is a key feature of the Coolster 125cc ATV Carburetor. Depending on the rider’s preferences and needs, the fuel-to-air ratio can be fine-tuned. Riders can improve their performance, fuel efficiency, and acceleration by adjusting the carburetor.

In addition to its ease of maintenance, the Coolster 125cc ATV Carburetor offers many other advantages. to maintain a smoothly running engine, the carburetor must be easy to disassemble and clean. The carburetor should be cleaned regularly to prevent clogs and other issues.

This popular ATV model is not complete without the Coolster 125cc ATV Carburetor. This bike is ideal for riders who want reliable performance on any terrain thanks to its high-quality components, adjustable design, and easy maintenance

The spark plug can become dirty, worn, or fouled over time, resulting in misfiring, poor performance, or failure to start. Maintaining peak performance of the ATV’s engine requires frequent inspection and replacement of the spark plug.

How to Clean Your Coolster 125cc ATV Carburetor? Step-by-Step Guide

  • Prepare a clean workspace by wearing safety glasses
  • Wash the exterior of the ATV carburetor with soapy water after removing it from the bike
  • Make sure the gasket on the float bowl is not damaged when removing it
  • Make sure the float pin and float assembly are in good condition by removing them and inspecting them
  • Ensure that the needle jet is not blocked or damaged by removing it and inspecting it
  • Make sure the pilot and main jets are not blocked or damaged by removing them
  • Be sure to turn the fuel air mixture screw all the way in and count the number of turns until it is fully tightened. In order to adjust the mixture upon reassembly, you will need this information.
  • Unscrew the screw regulating fuel air mixture
  • You need to remove the throttle adjustment screw
  • Clean all components thoroughly and inspect them for damage and obstructions. It is important to note that compressed air is incredibly helpful for clearing obstructions.
  • Any damaged seals, gaskets, or components should be replaced
  • Put the ATV carburetor back together in reverse order
  • To make assembly easier, lay out the parts in the order they were removed
  • Turn the mixture screw as many times as you recorded earlier to adjust the fuel to air ratio
  • The carburetor should be reinstalled on your ATV and the engine should be started. It may be necessary to make additional adjustments.

Clean Your Coolster 125cc ATV Carburetor
Clean Your Coolster 125cc ATV Carburetor

What are the Steps to Tune Your Coolster 125cc ATV Carb In The Field?

If you’re having trouble with your ATV carburetor, here’s what you should do if you’re stuck on the trails. If your ATV carburetor becomes blocked, damaged, or contaminated with fuel, or if mud is present in the air intake system, it may not be able to deliver the right amount of fuel to your ATV engine. The ideal situation is to tune your ATV carburetor yourself, but that’s not always possible. Here are some things you can do if you find yourself in a jam.

Visually inspect your ATV:

Make sure there are no signs of a fuel leak. Once you have the engine off, grasp the spark plug wire and make sure it is firmly attached to the engine. You should look for obvious signs of damage or dirt in the air intake. Battery attachment should be checked.

Tell someone where you are if you have a phone with signal and that your ATV isn’t working properly, if you have a signal. First and foremost, safety.

You should follow the carburetor tuning instructions carefully if you have an owner’s manual for your ATV. ATVs vary slightly from one another.

Are you still stuck? You don’t have an owner’s manual? Do you have a screwdriver? That’s fine. The air/fuel adjustment screw can be found by visually inspecting the ATV’s carburetor. Carburetors turn freely if you adjust them, they are not attached to an engine.

To adjust the carburetor:

Use a key, edge of a driver’s license, or anything small enough to fit in the carb adjustment screw. Turn the screw clockwise(inward) as far as it will go. You won’t be able to pull it out if you turn it outwards. Don’t force it too tight at first, but turn it inward all the way.

When the screw is fully turned in, the ATV will be in the lean position, very little fuel will pass through. After that, turn the screw out one quarter turn and try starting the engine. When an engine is in good working condition, the ideal setting is 1.5 to 3 turns out.

In the event that it does not start, or sputters and stops, turn the screw another quarter turn outwards and try again. Hopefully, the ATV will start and run without stalling after repeating this process.

At this point, it doesn’t matter if the engine sounds bad. When the engine is running without stalling, the air-to-fuel mixture will be close to what is needed to run the engine. If the engine runs without hesitation and sounds better, you can adjust it a bit more to improve the sound. Overturning it will eventually flood the engine with fuel, causing it to bog down and be difficult to start. Fuel will have to evaporate over time if it is flooded.

Make sure your ATV is taken to the garage or a shop as soon as possible:

The temperature of your ATV engine will rise if you run it too lean, and you will run the risk of burning a piston or damaging rings. Backfiring and valve damage are risks if you run it too rich.

If you take your ATV on the trails, always carry the owner’s manual, a small flashlight, and some basic tools with you.

Check to see if there are major elevation changes between where you are riding and where you are going before you plan a trip with your ATV. Changes in altitude may require an adjustment to the ATV carburetor to account for changes in air pressure. Higher altitudes decrease air pressure (adjust inward for more air), whereas lower altitudes increase air pressure (adjust outward for more fuel).

How To Adjust Your Coolster 125cc ATV Carburetor On The Trail?

While you should adjust your carburetor at home or at the shop, if an emergency occurs while you are riding, you may have to deal with it on the road.

The same technique can be used to wing ATV carburetor tuning (again, not recommended), but you may need to test the results a little at a time.

Your problem should correspond to the pilot screw you choose. In the event that you appear to be running rich, turn the pilot screw on the engine side of the carburetor. Choosing the pilot screw nearest the airbox will help you run lean.

Use a screwdriver, key, credit card, whatever you can find, and turn the pilot screw corresponding to your problem until it is flat against the carburetor.

Turn it the right way to prevent losing the screw if you turn it the wrong way!

The screw flat against the carburetor starts you in the lean position, where the screw can be loosened to add fuel or air. To tighten the screw, you’ll need to turn it one quarter turn. Check your engine’s performance after doing this 1 and a half times. It should work if it turns on without sputtering or stalling. When it doesn’t, turn it in one quarter turn. You want to get your engine to run as it should without overdoing it and flooding it. It can be worked on or someone else can work on it if you can get back to the truck or hauler afterward.

The majority of trial-and-error here can be eliminated if you bring your manual on your rides.

What are the Pros and Cons of a Coolster 125cc ATV Carburetor?

Pros of Carburetors

  • There is no need to spend a lot of money on carburetors.
  • Carburetors have a straightforward mechanism of operation.
  • Repairs and replacements of ATV carburetors are easy.
  • Engines don’t have carburetors integrated into them, so they can be replaced or serviced without affecting the engine.

Cons of Carburetors

  • Compared to fuel injection systems, carburetors are inefficient in design and function.
  • There is a tendency for carburetors to have slight lags which causes throttle response to be relatively slow.
  • Diaphragms, for example, are delicate components of carburetors that are more prone to damage.
  • Smoothness of the engine can be affected by an inconsistent air-fuel mixture.

Conclusion

Coolster 125cc ATV carburetors combine air and fuel into a combustible mixture to fuel the ATV. Basically, it ensures that the engine gets the right amount of fuel and air. During combustion, the carburetor draws in air and fuel and mixes them. Proper maintenance is required for the Coolster 125cc carburetor to function properly. ATVs can last longer if their carburetor is maintained and understood.




FAQ

How fast does a Coolster ATV go?

With a five-speed transmission, a Coolster 110cc can go up to 23 mph more than it does without a transmission. 125cc Coolster ATVs have a top speed of 25 mph, but with modifications, they can reach 40 mph.

How do I speed up my Coolster ATV?

To increase your top speed and power, there are several things that you can do. In moderation, you can use higher-grade fuels. Increasing airflow is another option. To improve suspension and handling, consider taking off unnecessary parts and replacing shocks with GZYF 11′′ 280mm Pair Rear Adjustable Air Shock Absorbers (view on Amazon).

Why should I clean my Coolster 125cc ATV carburetor?

Your carburetor may need cleaning if you have trouble starting your ATV, rough idling, poor acceleration, and decreased power and performance.

Are carburetors on Coolster 125cc ATVs easy to replace?

Having some mechanical knowledge and experience is needed to replace the carburetor yourself.

What should I do if my carburetor is not working?

The adjustment of a carburetor can be a complex process, and it is recommended that you hire a professional mechanic to do it. Follow the manufacturer’s instructions carefully if you intend to do it yourself and consult the ATV’s owner’s manual.