Chainsaw idle

If your chainsaw stalls instead of producing the reassuringly high-pitched sound of a healthy engine when you press the throttle trigger, something is interfering with efficient fuel combustion. The problem could be a lack of air or a misfiring spark plug, and both of these problems are easy to check and remedy.

Things might be a little more complicated if the problem is related to fuel delivery or to the composition of the fuel itself. A chainsaw has two filters to regulate air circulation and one to keep debris out of the fuel, and all of them need regular servicing. A dirty air filter -- which filters air coming through the intake port -- or spark arrestor -- which filters the exhaust -- impedes air circulation and kills the engine.

The air filter is under a cover on the engine housing, and the spark arrestor is between the exhaust port and the muffler. Both are easy to remove and service. A dirty fuel filter restricts fuel flow, which also kills the engine. The fuel filter is usually in the gas tank and easily removable and replaceable. If your chainsaw has been in storage, the fuel may need to be replaced.

When gasoline is left standing in the fuel lines and carburetor, it partially evaporates, leaving behind a varnish-like substance that clogs the fuel system. The fuel may also have moisture in it, and the moisture mixes with ethanol in the gasoline and settles at the bottom of the tank, which is where the fuel line is located.

The ethanol-water mixture clogs the fuel system.

Why Does My Chainsaw Chain Keep Turning?

When you remove the old fuel, you should disassemble the fuel lines and spray them with carburetor cleaner to dissolve deposits. An important part of diagnosis of engine stalling is to remove and examine the spark plug.

If the plug is excessively coated with carbon deposits, it's a sign that the fuel mixture in the combustion chamber is too rich. You'll probably also find excess deposits on the spark arrestor. On many chainsaw models, you can control the amount of fuel that the carburetor sprays into the combustion chamber by turning one of its adjustment screws. If the engine dies while idling, the idle adjustment needs to be tightened.

If the engine doesn't stall until you depress the throttle, tighten either the low-or high-speed adjustment screw to improve performance.When you finish a cut with your chainsaw and you release the throttle, you definitely want the chain to stop turning.

If it doesn't, and you make a false move, such as turning around too quickly, you could damage something or seriously injure someone. A simple carburetor adjustment may correct the problem. If it doesn't, then it could mean the clutch doesn't disengage. That's usually a sign that the clutch needs to be replaced. The most probable -- and easiest to fix -- cause of chain rotation while the chainsaw engine idles is a poorly adjusted idle setting on the carburetor.

The result is that too much fuel is delivered to the combustion chamber when the throttle is released, and the engine doesn't really slow. Correcting the problem requires adjusting the idle screw -- usually marked "I" --on the carburetor. The idle screw usually is near or behind the air filter. Adjust the screw to restrict fuel delivery by turning it clockwise with a screwdriver until the chain stops turning.

The saw must be running when you do this.

How to Adjust a Chain Saw Carburetor with a Tachometer

Turn the screw slightly counterclockwise if the engine starts to sputter. You may notice that in addition to the chain not stopping the chainsaw has other symptoms, such as smoking and the engine racing, which can be caused by a rich fuel mixture. Achieving better performance from the chainsaw may be possible by adjusting its low-speed carburetor screw -- usually marked "L" or "LA" -- to create a slightly leaner fuel mixture.

In order to do that, warm up the chainsaw's engine, and then, with the engine running, turn the low-speed carburetor screw clockwise one-quarter turn or less. A dirty air filter also can be responsible for an overly rich fuel mixture.

Take out the air filter, and, if it's salvageable, clean it with compressed air or by washing it with soapy water. Otherwise, replace the air filter. If the chainsaw's performance doesn't seem to be an issue, you can narrow the possible causes of the chain's problem to one: the clutch. A chainsaw is equipped with a centrifugal clutch, which is designed to engage the chain sprocket and the motor only when the throttle is engaged.

The centrifugal force generated when the engine spins forces the clutch shoes out to contact the clutch drum; when the engine stops, a set of springs retracts the shoes. When the clutch doesn't retract, the chain continues to spin, and the cause is either that the shoes are stuck or the springs are broken.

The process of servicing the clutch requires the removal of the chain sprocket, which can be tricky because the screw holding it is in its center, and the screw can't be turned without turning the sprocket. The remedy is to remove the spark plug and stuff a length of nylon rope into the piston cylinder to prevent the piston and engine flywheel from turning. After removing the sprocket, you may be able to get the brake shoes unstuck or replace the broken springs.

In most cases, however, the most effective repair is simply to unscrew the brake shoes from the flywheel and replace them. Chris Deziel has a bachelor's degree in physics and a master's degree in humanities. Besides having an abiding interest in popular science, Deziel has been active in the building and home design trades since As a landscape builder, he helped establish two gardening companies.

By Chris Deziel. Carburetor Idle Adjustment The most probable -- and easiest to fix -- cause of chain rotation while the chainsaw engine idles is a poorly adjusted idle setting on the carburetor.

Rich Fuel Mixture You may notice that in addition to the chain not stopping the chainsaw has other symptoms, such as smoking and the engine racing, which can be caused by a rich fuel mixture.

Clutch Malfunction If the chainsaw's performance doesn't seem to be an issue, you can narrow the possible causes of the chain's problem to one: the clutch. Clutch Maintenance The process of servicing the clutch requires the removal of the chain sprocket, which can be tricky because the screw holding it is in its center, and the screw can't be turned without turning the sprocket. Photo Credits. About the Author.If your Husqvarna chainsaw stalls at idle, it has a problem with the carb kit.

There are a few other minor issues that may cause stalling the engine. But, if the saw is under warranty period, it is wiser to have it fixed by the dealer. The chainsaw has a small engine that generates enough power to cut through.

chainsaw idle

The engine has several supportive parts that contribute so it can perform. But, the contributions they offer are important and we need each of them in good working condition.

There is no perfect machine in the world that runs without producing trouble. A chainsaw is not an exception here. But, to get the best out of your chainsaw, you need to maintain and troubleshoot it when necessary. In this article, we will be discussing the probable reasons and required troubleshoot process. Read the article carefully to learn the troubleshooting procedure of your Husky! A chainsaw engine has three basic modes, i.

We need the idle mode to be activated when we take a minor interval between two cuts. The idle mode is important as it disengages the engine from running the saw chain. Moreover, the idle mode increases our safety chain by disengaging the saw chain. Several interlinked parts contribute to pass the fuel into the combustion chamber.

As a result, one or more parts of this series may fail the combustion chamber to get the required fuel. So, we need to check each of them to figure out the faulty one. The chainsaw has a clutch plate that ensures the transformation of the engine from idle to working mode and vice versa. The spring gets the command from the clutch plate. If the clutch spring gets broken, your chainsaw has no way to retain the idle position and eventually stalls.

So, you need to check the clutch spring to see its condition. If the spring gets broken or its tension gets decreased, you need to replace the clutch spring. If the clutch spring is ok or you replaced it with a new one, but the chainsaw stalls, move on to the next step. The spark plug is the only part that supplies the required spark to the combustion chamber. If the spark plug fails to provide necessary sparks at idle mode to keep alive the engine, the engine will stall.

So, it is important to have the spark-plug in working condition. Furthermore, there is an arrestor that helps the combustion chamber to arrest the spark coming from the spark plug. Like the spark plug, the arrestor also needs to be in working condition. Locate the spark plug and spark arrestor on your chainsaw. Take out the spark plug and arrestor to see whether they are in good working condition. The arrestor is a pretty transparent layer of carbon clothing.

If it is in good condition, you will be able to look through it. If it clogged, clean it using alcohol. Check the spark plug for carbon blockage.

Clean the spark plug with kerosene. If the spark plug or arrestor or both are not in good condition, you need to replace them.

chainsaw idle

Place both the parts into their respective positions. Give your chainsaw a functional test run. If it still stalls at idle, move on to the next step.It's not fun trying to handle timber with a chainsaw that won't idle. Using a chainsaw is dangerous enough without having to balance the throttle to stop it from stalling.

So why won't your chainsaw idle? The problem is usually a blocked air filter or an idle screw out of adjustment, other possible causes include:. Chainsaws are 2 stroke engines and they are fitted with a small very finely balanced carburetor. Any change to this ratio will cause poor performance, a blockage in either the fuel or air and it just won't run right, especially at idle.

Needless to say the gas should be fresh and mixed to the correct ratio for your saw. Old gas will cause all kinds of poor performance problems. Too much oil in the gas can cause the plug to misfire, and too little runs the risk of damaging the engine. The spark plug should be clean and gaped correctly, I like to have a new plug handy, makes troubleshooting a saw a lot easier. The spark arrester muffler can block causing poor performance and problem idling. The muffler can be removed for inspection and cleaning.

Plug should be clean and gaped to spec. The gas should be fresh and mixed to the correct ratio for your saw. Too much oil in the gas mix will cause the plug to oil and misfire, and as you know, too little will damage the engine. Cleaning the air filter is the obvious place to start, they get pretty dirty. Chainsaws as you know, throw out a lot of dust and debris, some saws run a turbo type system where air is directed towards the carburettor, and it's up to the filter to catch all this crap.

All modern chainsaws have tool-less air filter covers, which makes accessing them really easy. Air filters differ from saw to saw some have a fine mesh screen and others will have a fabric or foam filter. Compressed air is the best way to clean them but not everyone has a compressor so make do with tapping it on a flat solid surface to loosen up the debris. A clean rag or better, a bristled brush will clean it out in no time. Typically filters last a long time as they are designed to be durable.

However, i f your filter has a hole in it or you see a lot of debris in the intake of the saw, you'll need a new filter. Pull the choke on the saw before removing the filter, it stops dirt from dropping into the carburettor.Although it's common to adjust the idle and low-speed screws on a chain saw without a tachometer, the tachometer is necessary to make what is perhaps the most important adjustment: the high-speed setting.

Almost all chain saw carburetors have these three setting screws, and they are usually indicated by the letters "I," "L" and "H," respectively. The two tools needed to make the proper adjustments include a screwdriver for turning the screws and the tachometer for recording engine speed.

Carb Adjust on Poulon Pro 42cc Chainsaw

Older tachometers clip to the spark plug wire, but newer digital tachometers record revolutions per minute, or rpm, without the need for a physical connection.

Remove the chain saw's air filter, and clean it. If you can't get it clean with compressed air or soap and water, replace it with a new air filter. A dirty air filter affects engine speed and will give you faulty readings. Fill the chain saw's tank with the proper fuel-oil mixture for your saw. If the mixture has been in the tank for six months or longer, drain the tank and fill it with fresh fuel-oil mixture. Always adjust the carburetor when the chain saw has a full tank, or else the settings will produce a rich fuel mixture the next time you refuel the chain saw.

Start the chain saw's engine, and let it idle for about three to four minutes. If you can't get the saw to start and you think it has a bad idle adjustment, turn the "I" screw all the way clockwise, start the saw and turn the screw counterclockwise until the chain stops turning.

Adjust the idle by turning the "I" screw clockwise until the chain starts to turn. Turn that screw the other way until the chain stops. Record the engine speed with a tachometer, either by clipping the tachometer's alligator clip to the spark plug wire about 2 inches from the spark plug or, if you have a digital tachometer, by hovering the tachometer over the spark plug.

Compare the idle speed with the specifications for your saw as listed in its operator's manual. The idle speed for most saws is about 2, to 2, rpm. Adjust the idle speed to match the speed specified for your saw. If you don't have the saw's operator's manual, you should be able to find a copy of it online by inputting the saw's make and model in a search engine. Turn the "L" screw clockwise until the engine begins to starve for fuel and die, and note the screw's position.

Turn the screw the other way until you notice the opposite effect: the saw is getting too much fuel and stalling. Set the screw midway between those two points. Engage the throttle, and with the engine running at full speed, turn the "H" screw clockwise until the engine races. Record the engine speed with the tachometer. Look up your chain saw's maximum safe speed in the operator's manual. If the tachometer reads more than that speed, turn the "H" screw counterclockwise until the speed falls below the maximum safe speed value.

Keep turning the "H" screw until the engine starts to run with a fuller sound as the carburetor gets more fuel. At some point, it will begin to stall. Try to find the mid-point between the maximum safe speed for the saw and the point at which the engine starts to die. Chris Deziel has a bachelor's degree in physics and a master's degree in humanities.

Besides having an abiding interest in popular science, Deziel has been active in the building and home design trades since As a landscape builder, he helped establish two gardening companies. By Chris Deziel. Things Needed. Photo Credits. About the Author.If your chainsaw engine dies at full throttle, check the following parts: the carburetor, fuel lines, fuel filter, air filter, and muffler.

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Call volumes are high, please use our self-serve options to cancel or return your order. Chain Saw: Engine Will Idle But Dies At Full Throttle If your chainsaw engine dies at full throttle, check the following parts: the carburetor, fuel lines, fuel filter, air filter, and muffler.

Your carburetor is tasked with mixing fuel and air in the correct ratio, so that combustion can occur, and your chainsaw will run. When the carb becomes clogged which is often the result of old fuel sitting in it over a long period of time, like over the winterit will not perform this task effectively. This is particularly true when you attempt to run your chainsaw on full throttle. You may be able to purchase a carb kit, and clean and rebuild the carb, rather than replacing it.

But if the carb itself is damaged or corroded internally, which you will notice while you tear it down with your carb kit, you will need to replace it.

Find your Carburetors here. The air filter in your chainsaw protects your chainsaw from dirt and debris by filtering it out before it can reach the engine. This dirt and debris can build up and create a clog.

When a clog occurs, your engine will not get enough air to operate effectively. In this case, the filter is likely only partially clogged, so it will allow enough air to the engine for it to run on idle, but not enough to sustain full throttle. You should clean your air filter regularly to avoid this issue.

Fortunately, air filters are easy to locate on top of the carburetor — clean and replace if necessary. Find your Air Filters here. Like the air filter, the fuel filter is designed to protect the engine from dirt and debris. While the air filter protects it from airborne particles, the fuel filter protects it from particles found in the fuel. If the filter becomes clogged, not enough fuel will reach the engine for it to run properly.

Because your chainsaw will idle, but dies when it is revved up to full power, it means that the filter is only partially clogged; it will allow enough fuel to the engine to run on idle, but not enough to sustain full throttle. Disconnect the fuel filter from the fuel lines, and at this point you can either clean or replace the filter to solve this problem.

Cleaning and potentially replacing your fuel filter should be part of routine maintenance for your chainsaw.

chainsaw idle

Like the air filter, it is an inexpensive part to replace, but greatly Like the air filter, it is an inexpensive part to replace, but greatly affects performance. Find your Fuel Filters here. Over time, when your chainsaw has been running on full throttle, carbon deposits can build up in the exhaust port, muffler, or spark arrestor.

This can result in one or more of these parts becoming clogged. When such a clog occurs, the exhaust gasses will not be able to exit the engine, and it will cause your chainsaw to die. This type of carbon buildup should be visible, and the offending part should be replaced. Find your Mufflers here. A carb kit can be purchased to help clean and rebuild a plugged carburetor. For more information, as to how a carburetor can cause this symptom, please see our carburetor section.

Start with the air filter housing filter and air filter, and take off the bolts holding down the carb and gasket.For chainsaw carburetors, balance is critical. The carburetor idle controls the ratio of fuel to air coursing through the engine.

When there's too little fuel, the engine will run "lean" and won't have enough power, so using it as intended can cause engine damage. If too much fuel mixes with air, it runs "rich," and could choke up and bog down, produce excess smoke, or waste gas. Changing the idle on a chainsaw carburetor isn't complicated, but getting the right mix can take practice. A new chainsaw will be properly tuned, but over time the idle will need adjusting. After you strike the perfect idle, your chainsaw will cut efficiently and smoothly.

As the saying goes, if it isn't broken, don't fix it. If you start the chainsaw easily, and it runs smoothly, the idle's doing just fine and there's no need to tinker with it.

So when should you adjust the idle? If the chainsaw's being stubborn and is hard to start, that's an indicator that the fuel and air mix are off. If it roars to life, but then falters and shuts off, that's a problem often caused by the idle. Finally, if the chainsaw stalls out and dies when it's working under a load, that's usually an idle problem as well. A clogged air filter will complicate any attempt to adjust your idle.

With the dust, dirt and oil chainsaws are routinely exposed to, experts recommend cleaning filters after five hours of run-time. To clean your filter, if it's not obvious where the air filter is, check your owner's manual. It's usually a raised, round cover that you can take off after removing some screws. Then, the filter is usually easy to lift off its seat. Different filters may have different care suggestions, but many will be easily cleaned with warm, sudsy water once you've tapped off any excess dirt and debris.

After some gentle scrubbing and a rinse with clean water, let it dry, andthe filter should be as good as new. Adjusting the idle on a chainsaw all comes down to the turn of a T-head screw. On right-handed chainsaws, the idle screw tends to be on the left.

It's best to check the owner's manual, or do a web search for your make and model, to ensure you've found the proper screw or screws to adjust. You'll either tweak a single screw or three separate ones, but the premise is the same in both instances. To find out your starting point, fire up your chainsaw and get a flat-head screwdriver ready.

These T-head timing screws are extremely sensitive to turning, so work at most with quarter-turn increments with your flat-head screwdriver on the T-screw, and make mental notes as you go. When turning the screw clockwise or counterclockwise, watch for when the engine's behavior changes both while you're throttling it but also when idling.

If the chainsaw won't stop spinning when idling, or it's smoking when it idles, it's getting too much fuel and running rich, so you'll need to back it down a bit.

How To Troubleshoot And Adjust The Idle On A Chainsaw

If it's accelerating too slowly, or sputters and jumps erratically when idling, it's got too little fuel and needs more. Take note of where the screw is when it runs lean or rich.

Clockwise is generally the direction you turn to make the mixture leaner, and counterclockwise usually makes it richer. The sweet spot for the perfect idle is usually halfway between these two points. If your carb has three screws to tweak, you'll see labels. Three-screw carbs are trickier to tune, so be careful when adjusting the high-speed performance screw. First, locate the "LA" screw. This controls the general engine idle-speed, and tweaking its performance is much like the single-screw carburetor adjustment above.

Start by adjusting this screw as you would for the single-screw carbs. The "L" screw is for low-speed adjustment. Adjust this screw second. The "H" screw is for high-speed adjustment.