• Skip to main content
  • Skip to secondary menu
  • Skip to primary sidebar
  • Skip to footer
  • Home
  • About Us
  • Privacy / Disclaimer
  • Contact Us
  • Contributing Writers
  • Site Directory

Chainsaw Journal

Expert Advice on the Modern Home, DIY, Power Tools & Outdoor Power Equipment to help you make intelligent buying decisions.

  • Generators
    • Portable Generators
    • Portable Power Stations
    • Inverter Generators / Quiet
    • Educational
  • Chainsaws
    • Cordless / Battery-Powered
    • Corded-Electric
    • Gas-Powered
    • Chainsaw Reviews
    • Education / How-to
  • Power Equipment
    • Log Splitters
    • Snow Blowers
    • Wood Chippers / Shredders
    • Portable Table Saw
    • Leaf Blowers
    • Lawn Mower
    • Miter Saws
    • Outdoor Cooking
  • Workshop Tools
    • Shop Heaters
    • Woodworking tools
    • Table Saws
    • Automotive
    • Air Compressors
  • Pools
    • Robotic Pool Cleaners
    • Pool Pumps
    • Pool Heaters
  • Indoor Home
    • Air Conditioners
    • Vacuum Cleaners
  • Informative
  • Kids
  • Blog
Home » Blog » Chainsaw Won’t Idle, What’s Wrong?

Chainsaw Won’t Idle, What’s Wrong?

Last Updated: March 16, 2023 / at: 8:57 am

My chainsaw won't idle, what's the problem?

Here’s a common problem : Your chainsaw won’t idle and you have work to get done, what do you do? Most of us expect our tools to work all the time, whenever we need them to. In fact, we never wonder if our car will start, or if our oven will turn on, or if our television will work just as we’re about to turn it on to watch our favorite show. Chainsaws, and other mechanical tools are a little different. They do fail us from time to time and they require maintenance.

Table of Contents —
  1. What do you Do if your Chainsaw Won’t Idle?
    1. How do gas-powered chainsaws work?
      1. Why won’t my chainsaw idle?
    2. Tuning the carburetor
    3. Faulty centrifugal clutch

There are many reasons why a chainsaw won’t idle properly, and in this article we’re going to present a step-by-step process which will help you find the issue and rectify it before it causes any additional damage.

What do you Do if your Chainsaw Won’t Idle?

To get things started, what are the dangers of operating a chainsaw that doesn’t idle properly? Well, it depends on what type of idling issue we are talking about. Sometimes, your chainsaw will only idle for about 5 to 10 seconds after you let off the throttle and then it will shut down. On the other hand, there will be cases in which the chainsaw refuses to lower its rpm when you get off the throttle. This can be extremely dangerous, because the chain keeps spinning even when you aren’t holding on to the trigger and it can catch you when you least expect it, causing deep injuries.

A slightly less catastrophic version of idling issues manifests itself in the form of delayed or weak throttle response. This is when you hit the trigger hard right before plunging the bar into a log of wood, and instead of immediately revving up to high rpm like it should, the chainsaw instead takes its time. In some cases, the chainsaw will eventually get to its high rpm speed, in other cases it will not go beyond the low to mid rpm range no matter how hard you press the trigger.

In order to understand and correct these issues, we must take apart the chainsaw and inspect its powerhead (the section of a chainsaw which contains the motor, fuel, air filter, etc.). Note that this article is intended for gas powered chainsaws only, because idling is something that only internal combustion engines do. Electric motors operate in a completely different manner and can start/ stop instantly with immediate torque, without requiring them to remain in a standby state whenever you aren’t using the chainsaw.

VIDEO | Repairing a Chainsaw that wont’ idle

YouTube video

How do gas-powered chainsaws work?

Chainsaws are powered by single cylinder 2-stroke engines which rely on an air-fuel mixture in order to generate power. The air- fuel mixture is created in the carburetor, which sucks in atmospheric air through an air filter and mixes it in a very specific ratio with fuel that it pulls from the gas tank of the chainsaw. The gas tank isn’t just an airtight container for fuel, it also packs a little fuel filter which separates all the sawdust and impurities from fuel before it is allowed to enter the fuel line and reach the carburetor.

Once the air-fuel mixture reaches inside the cylinder of the engine after passing through an intake boot (a rubber hose connecting the intake of the engine with the output of the carburetor), it is ignited by an electric spark. This spark happens when high voltage is generated between the insulated inner electrode of the spark plug, and the outer grounded terminal. Air fuel mixture is in aerosol form, and its properties change when subjected to the high electric potential difference of several thousand volts between the two electrodes.

Once the voltage exceeds dielectric strength of this gas, it ionizes the gas and makes it act like a conductor, which causes electricity to flow between the two terminals of the spark plug. This ignites the mixture, causing an explosive effect that pushes the piston down. The crankshaft takes this linear motion and converts it into rotational force which is transferred to the centrifugal clutch.

Centrifugal clutches are used in small 2- stroke engines and consist of 3 or more spring- loaded “clutch pawls” that engage once the centrifugal forces exceed the tension load of the coil springs holding them (happens when the engine speed goes beyond idling rpm levels). These pawls or shoes press against the inside of a clutch drum which is directly connected with a drive sprocket that turns the saw chain around the guide bar.

VIDEO | STIHL Chainsaw Won’t Idle

YouTube video

Why won’t my chainsaw idle?

As we explained earlier, there could be various reasons. Maybe the air filter is clogged, so the engine is running an air fuel mixture that is too rich which is resulting in loss of power and dull throttle response. It could also be a jammed up spark arrestor which happens when you put too much oil in the gas- oil fuel mix, this results in a whole lot of unburned material since oil combusts at a much higher temperature than gas and this soot clogs up the spark arrestor preventing exhaust gasses for escaping freely. Spark plugs with corroded electrodes might also be the culprit, and we all know that you can’t have a fire without a spark. Or maybe you have a spark, but it is too weak because of carbon buildup around the electrodes, which results in incomplete combustion of the fuel- air mix. Most major chainsaw manufacturers like Stihl recommend that you replace the spark plug every 100 service hours (that’s twenty 5- hour workdays).

You might want to check the fuel line and fuel filter within the gas tank. Sometimes, the ethanol in cheaper gas will corrode the soft rubber tubing that carries fuel from the tank to the carburetor. You can flash a light into the tank after emptying it, and if you see holes or cracks in the fuel line, it is time for a change. Might as well change out the fuel filter while you’re at it, since those are pretty cheap anyways. A bad fuel line will cause the chainsaw to run lean (too little fuel or too much air in the mixture), and this means it will only run at idle for 5 to 10 seconds before it shuts off completely.

Running a lean mixture for too long will cause irreversible damage to the internals of the engine. An air leak around the intake boot or head gaskets will result in lower compression pressures and your chainsaw won’t idle properly. You can tug the starter rope to get a feel for the compression levels, or you can take the chainsaw to a shop where they will do a compression test.

Finally, you definitely want to check the adjustment screws on the carburetor since these screws control little needle valves which determine how rich/ lean the air fuel mixture is at various rpm levels (idle, low, and high). Every modern chainsaw should come with at least 2 adjustment screws, one for low and the other for high rpms. It is recommended that you never tamper with the high adjustment screw because it is very easy to blow your chainsaw engine if you set it too aggressively. Which is why, manufacturers often install limiter caps on the screws which prevent you from screwing up the carburetor and engine tune beyond repair.

✓ If your chainsaw won’t start, not even an idle, then read : Why Won’t My Chainsaw Start?

VIDEO | Chainsaw Maintenance from Husqvarna

YouTube video

Tuning the carburetor

When you want to tune the carburetor, we highly recommend referring to your chainsaw owner’s manual since different companies use different labels for these adjustments. Stihl uses “H”, “L” and “LA” which stand for HIGH, LOW, and IDLE respectively. Husqvarna uses “L”, “H”, and “T” which means LOW, HIGH, AND IDLE.

By default, the needle valves are set from the factory such that the chainsaw delivers optimum power output with good fuel efficiency. You will find that in some owner’s manuals they recommend that you run the chainsaw with a richer mix than usual for the first few hours after you’ve purchased it. Then you can take it to an authorized dealer or chainsaw shop for precision carb tuning where they will adjust the HIGH rpm fuel mix for you. We recommend purchasing a handheld digital tachometer if you want to reliably tune your chainsaw’s idle and high rpm speeds. Just point it at the spark plug and it will tell you the rpm of the engine.

Generally speaking, driving the T- screw in on a carburetor means the engine will get a leaner air- fuel mix which allows for higher rpm. Turning the screw counter- clockwise will pull it outwards which delivers a richer air- fuel mix to the engine, resulting in lower rpm. You want to find a sweet spot, not too low nor too rich. Adjust the low and idle screws first before you start tinkering with the high rpm settings. And make sure that the air filter is clean, and that the spark plugs are functioning properly before you tune the carburetor.

VIDEO | How to Tune Chainsaw Carburetor

YouTube video

Faulty centrifugal clutch

One of the most common reasons a chainsaw chain creeps forward or keeps spinning even when the engine rpm is at idle, is a faulty clutch. It could be an issue with the return springs in the clutch. One of them may be broken, which means the clutch shoes don’t return to their resting position when the engine slows down, causing the drive sprocket to keep spinning. Another possible issue is a dirty clutch drum with dried up, caked residue inside that shortens the amount of distance the clutch pads have to travel before they engage with the drum. Take some brake cleaner and wipe the inside of the clutch drum clean if that is the case.

Last Updated: March 16, 2023 at 8:57 AM / by Chainsaw Journal

Primary Sidebar

🐭 Quiet Backup Power

2023 Reviews – Best Dual-Fuel Inverter Generator / Top Rated Models

2023 Reviews – Best Dual-Fuel Inverter Generator / Top Rated Models

Last Update ► March 23, 2023

Choosing the best dual-fuel inverter generator is a little more difficult today than it was only a year ago as many new, high-quality models have entered the market, & they're fantastic...

🌍 Clean Energy Chainsaws

Guide to the Best Electric Chainsaws for 2023 — Expert Reviews

Guide to the Best Electric Chainsaws for 2023 — Expert Reviews

Last Updated February 6, 2023

You'll find a lot of differing opinions on what the best electric chainsaw is. The reason is because there is no right answer. I know, this might...

🐶 Keep A Tidy Yard…

Reviews : Best Resin Shed in 2023? Backyard Storage, Big & Small

Reviews : Best Resin Shed in 2023? Backyard Storage, Big & Small

Last Update ► February 26, 2023

Resin backyard storage sheds are a great addition to any home or garden. Made from durable, weather-resistant materials, these sheds offer a convenient and secure way to store tools, equipment, and other outdoor essentials.

🪑 The Craft of Wood Turning

Reviews – Best Wood Lathes from WEN, JET, Powermatic & More

Reviews – Best Wood Lathes from WEN, JET, Powermatic & More

Last Update ► March 21, 2023

There are some tools that separate the best from the rest. I consider a wood lathe to be one of these. A machine that shows you’re a true craftsman. If you’re interested in buying the best wood lathe, you have my greatest respect. Using these machines, you’re able to turn perfectly molded ornate pieces, cut precision holes for screwless joins, and a lot more.

👂🏼 Quiet RV Power

2023 Picks : Best RV Generator | Quiet Inverter & Power Stations

2023 Picks : Best RV Generator | Quiet Inverter & Power Stations

Last Updated March 12, 2023

What's the best RV generator for you in 2023? Lucky for you, big brands offer some exceptional inverter generators in a wide range of power output and price points. So, don't worry, there's something here for everyone. I'm focusing on inverter generators because it's essential to have a quiet generator for your RV

☄️ Home Emergency Backup

2023 Reviews : Best 9500 Watt Generators / New Models with CO Sensors

2023 Reviews : Best 9500 Watt Generators / New Models with CO Sensors

Last Update ► January 5, 2023

Look no further, above you will see the Westinghouse WGen9500c generator --- one of the best 9500 watt generators you can buy. Period!

🔥 Intelligent Pool Heaters

Review Guide − Best 400,000 BTU Pool Heater / NG + Propane

Review Guide − Best 400,000 BTU Pool Heater / NG + Propane

Last Update ► February 15, 2023

Back in 2020 I'm sure a lot of us wondered if we'd ever make it to 2023, and here we are. We made it! The world is slowly going back to normal and now we're looking to find a fast-heating and energy efficient, 400,000 BTU pool heater. Why?

🐱 The Future is Cordless

Best Cordless Chainsaw 2023 Buying Guide – Chainsaw Journal

Best Cordless Chainsaw 2023 Buying Guide – Chainsaw Journal

Last Update ► March 7, 2023

What's the best cordless chainsaw for 2023? If you're smart you'll take our advice and choose from our list of fantastic battery-powered chainsaws.

🌲 Firewood Facts…

2023 : How Much is a Cord of Wood? — & More Firewood Facts.

2023 : How Much is a Cord of Wood? — & More Firewood Facts.

Last Updated February 24, 2023

This article focuses on the always popular topic of firewood. It’s an essential thing for many people. Wood, we need it.

💨 Prepare for the Worst

2023 REVIEWS : Best Portable Power Station for CPAP / Top Picks

2023 REVIEWS : Best Portable Power Station for CPAP / Top Picks

Last Update ► February 14, 2023

What's the Best Portable Power Station for a CPAP? If you're using a CPAP machine at night the last thing you want to worry about is having the power go in the middle of the night ---

🌟 Clean, Portable Power

2023 Reviews : Best Camping Generator & RV / Quiet Inverter & Battery Power

2023 Reviews : Best Camping Generator & RV / Quiet Inverter & Battery Power

Last Updated March 7, 2023

Generators come in a variety to types, which you may or may not be aware of. Everyone has different needs when it comes to choosing the best camping generator their needs. The question is how much power do you need? What's your budget? Are you looking for an inverter generator or a portable power station?

🪑 For Work or Play

Reviews – What’s the Best Table Saw Under $1000?

Reviews – What’s the Best Table Saw Under $1000?

Last Updated February 10, 2023

A good portable table saw can easily be had for under $1000, but you won't be able to find a quality cabinet saw for that amount. This guide will save you a lot of time.

☄️Never Let the Power Die

Reviews— Best Dual Fuel Portable Generator / Gas & Inverters

Reviews— Best Dual Fuel Portable Generator / Gas & Inverters

Last Update ► February 12, 2023

What's the best dual-fuel portable generator in 2023? Well, like the answer to most questions in life, my answer is, "It depends."

🔥 Affordable Log Splitters

Reviews of the Best Log Splitters under $1000 for Winter 2023/23

Reviews of the Best Log Splitters under $1000 for Winter 2023/23

Last Updated March 21, 2023

A log splitter is the evolution of the axe in the same way that cars are the evolution of horse drawn carriages. If you use a lot of firewood in the winter then investing in a high quality log splitter is probably a wise choice.

🌒 Whisper-Quiet Clean Power

2023 Update : Westinghouse iGen4500 Review / iGen4500c CO Sensor

2023 Update : Westinghouse iGen4500 Review / iGen4500c CO Sensor

Last Update ► March 6, 2023

Well, the Westinghouse Electric Company built their first commercial electric power station in 1886 to supply Great Barrington, Massachusetts. Since then...

💎 The Most for your Money

2023 Reviews : Best Chainsaws for the Money  / Top Value Models

2023 Reviews : Best Chainsaws for the Money / Top Value Models

Last Update ► March 10, 2023

We have a chainsaw for a wide range of applications and budgets. I know the needs of consumers vary and there's no such thing as the "best" chainsaw for everybody. Whether you have a budget of under $100 or over $300 to buy a PRO-grade chainsaw, I have options for you to consider.

❄️ For Heavy Snow…

2023 REVIEWS – Husqvarna ST224 2-Stage vs TORO 60V Cordless

2023 REVIEWS – Husqvarna ST224 2-Stage vs TORO 60V Cordless

Last Update ► March 12, 2023

In this Husqvarna ST224 review you'll see why this has been a top selling two-stage snow blower for years ---

🔋 Compare New Explorer PRO

REVIEW — Jackery Explorer 1000 + PRO E1000 / Best Solar Power Station

REVIEW — Jackery Explorer 1000 + PRO E1000 / Best Solar Power Station

Last Update ► March 11, 2023

Welcome to my review of the the Jackery Explorer 1000. Jackery stands out as one of the best manufacturers of portable battery power stations and solar generators.

🍀 Shred Yard Debris

Reviews : Best Chipper/Shredder in 2023 — Gas & Electric

Reviews : Best Chipper/Shredder in 2023 — Gas & Electric

Last Updated February 22, 2023

What's the best chipper/shredder for 2023? Keeping your lawn neat, tidy and clean requires a lot of work and tools. A chipper/shredder is one of better ways to spend your money for your home, alongside of a generator, lawn mower and chainsaw.

🔥 Time to Split Firewood

Reviews – Best 22 to 30-Ton Log Splitters / New Top Rated Models

Reviews – Best 22 to 30-Ton Log Splitters / New Top Rated Models

Last Update ► March 11, 2023

Welcome! 2023 is a great year to buy a log splitter. New machines are here for us to discuss. The Swisher LS22E is one of the best 22-ton electric log splitters available today. You can see it above. It's a standout among the crowd of "me too" models. It's a 120V electric 22-ton splitter and works with any standard home outlet.

👩🏻‍🦰 Watch Out Trees!

2023 Review — Husqvarna 460 Rancher / Top Rated Gas Chainsaws

2023 Review — Husqvarna 460 Rancher / Top Rated Gas Chainsaws

Last Update ► March 16, 2023

The 460 Rancher is designed for homeowners, farmers and ranchers who have a need to fell large trees in a single cut (or two), to cut firewood or to harvest large timber.

🍂 Ergonomic Leaf Blower

2023 Reviews : Best Backpack Leaf Blower / Top Rated Models

2023 Reviews : Best Backpack Leaf Blower / Top Rated Models

Last Update ► March 4, 2023

I think you'll be surprised to learn that in 2023, reputable brands are making cordless backpack leaf blowers that are equal to, or more powerful than many gas backpack leaf blowers --- and they're cheaper.

🍰 Generator Sweet Spot

Reviews — Best 7500 Watt Generators for the Money / New Models

Reviews — Best 7500 Watt Generators for the Money / New Models

Last Update ► January 24, 2023

As far as value, you won't find a better overall generator than this WGen7500 series from Westinghouse. For starters, Westinghouse has been in business since 1886 so they know how to make generators, among other things. For 2023, this is the best 7500 watt generator for homeowners looking for emergency backup power.

💡 The Power of 3 Fuels

Reviews : Champion 100416 vs DuroMax HXT — Best Tri-Fuel Generator

Reviews : Champion 100416 vs DuroMax HXT — Best Tri-Fuel Generator

Last Update ► February 20, 2023

A tri-fuel generator is quite a novel concept. I’m sure not too many folks are aware they even exist. Hybrid generators have become common. Most of us know a bit about dual-fuel generators. These can run on propane or gasoline, making them very convenient. An obvious question, I’m sure many of you are asking has to be: What is a tri-fuel generator?

👷🏼 For DIY & Construction

Reviews : What’s the Best Jackhammer in 2023? Electric & Pneumatic

Reviews : What’s the Best Jackhammer in 2023? Electric & Pneumatic

Last Updated February 21, 2023

What's the Best Jackhammer for you? How much breaking force do you need? For work or for home? We cover a wide range of jackhammer's so you can choose the one that matches your needs (and budget)

🥾 Heavy-Duty Generators

Reviews : Best Jobsite Generators  — Buying Guide : OSHA / GFCI

Reviews : Best Jobsite Generators — Buying Guide : OSHA / GFCI

Last Updated March 1, 2023

2023 has been an incredible year for the portable generator market. The biggest brands have been releasing innovative new models at very competitive prices. The Champion PRO 100430 is a new commercial generator, packed with practical features you'll need if you're a contractor.

⚡️ Powerful Generators…

2023 Reviews : Best 12000 Watt Generators | New Top Rated Models

2023 Reviews : Best 12000 Watt Generators | New Top Rated Models

Last Updated January 23, 2023

What do you need it for and what's your budget? We take a deep dive and review many great 12000W generators.

✨ Versatile Generator

2023 Reviews : Best 240 Volt Inverter Generators / New Models

2023 Reviews : Best 240 Volt Inverter Generators / New Models

Last Updated March 19, 2023

If you’re looking for a 240V inverter generator, it can be challenging. There simply aren’t too many on the market. This buying guide and review is the best place to begin your search for a 240V inverter generator.

Footer

DMCA.com Protection Status
  • Return to HOME
Do Not Sell My Personal Information

1199 Marinaside Crescent, Vancouver, Canada
T: 604/437/8033

© 2014–2023 • Chainsaw Journal • Affiliate Disclaimer • —Stay Strong

  • This site contains affiliate links. If you make a purchase with our product links we may receive a small commission at NO COST TO YOU.(Learn More)