Chainsaw Chain Won’t Tighten? Here’s How You FIX It!

chainsaw chain won't tighten - featured image

Don’t even try to DENY it!

Proper chain tensioning is an important part of chainsaw maintenance. ❗

Chains that are too loose can come off the bar or spin wildly, while chains that are extremely tight can create unnecessary wear and tear on the bar and sprocket.

But what if your chainsaw chain won’t tighten?

Here are 5 possible reasons why a chainsaw chain won’t tighten:

  1. Stripped chain tensioner screw
  2. Stretched out chain
  3. Using the wrong size chain
  4. Worn-out chain sprocket
  5. Engaged chain brake

Btw, I’m Sam & I’ve been using chainsaws for more than two decades 😎. In this article, I’m going to show you how you can solve all these issues.

Are you READY? 

Let’s get started…

Your Chain Tensioner Screw isn't Working

Probably the most common cause of a chainsaw chain that won’t tighten is the tensioner screw simply not doing its job. This could be due to various reasons. But 90% of the time, it happens when the threads on your chain tensioner screw get stripped.

In that case, no matter how hard you try, your chain won’t tighten!

An example of a chainsaw chain tensioning screw with stripped threads.

About 3-4 days ago, the chain on one of my saws wouldn’t stay tight.

After some troubleshooting, I figured out that the threads on the tensioner screw were literally RIPPED OFF!

So I just replaced it immediately (it cost me around 7 bucks), and VOILA! The chain was back in action.

How to Tell if Your Chain Tensioner is Okay?

  1. Loosen the bar nuts & take off the clutch cover.
  2. Inspect the tensioning screw for any damage or signs of wear.
  3. Try to tension the screw while holding the clutch cover in your hand.
  4. If the screw doesn’t move or get stuck, it means that the tensioner isn’t working properly.
testing chainsaw tensioner screw

How Do You Fix it?

If your tensioner is indeed damaged or not working, it’s better to replace it. It wouldn’t cost you more than 10 bucks

I usually prefer ordering online because I get offers, but you can also go for the nearest dealer store.

Btw, here’s a SUPER informative video tutorial that walks you through the full process step-by-step: 👇

Your Chain has Stretched Too Much

A stretched chain is another common reason why you might be facing this issue.

Let me explain:

Chainsaw chains get stretched when they’re hot (which occurs naturally while cutting). And to be honest, a little bit of stretching is NORMAL for any chain.

loose chainsaw chain

But there’s a catch!

When a chain gets extremely hot, it stretches to a level where the tensioner just won’t work. At that point, no matter how much you sweat it out, the chain won’t tighten!

new vs stretched out chainsaw chain

What Causes a Chainsaw Chain to Stretch Too Much?

Well, there’re tons of reasons that might cause a chainsaw chain to stretch, including – 👇

  1. Clogged or blocked oiler holes,
  2. Cutting hardwood (i.e. oak, maple, or hickory),
  3. Improper sharpness of the chain,
  4. Cutting dirty wood,
  5. Extremely tight chain,
  6. Inadequate chain lubrication,
  7. Running out of bar and chain oil while cutting, and many many more!

The worst part?

If you keep using a stretched out chain, you might end up damaging your chain sprocket & bar.

A chain that keeps coming off the guide bar.

What's the Solution?

If your chain has stretched beyond the limit and won’t tighten, the only (and probably the “safest”) solution would be to replace it ASAP!

Some NERDS might tell you to shorten the chain by removing a couple of links. But trust me, it doesn’t work all the time!

You're Probably Using the Wrong Size Chain

Yesterday my wife was complaining that her chainsaw chain won’t tighten. So, I quickly took a look.

Can you guess what I found?

Yup, she was using an oversize chain! The pitch and gauge were correct, but the drive link count was wrong.

It was a 78-link chain, but the saw only needed 72. That’s why it was too loose and wouldn’t tighten.

(I won’t blame her. My workshop is a mess with hundreds of chains lying around!)

How to Check If You've Got the Right Size Chain?

Well, it’s not that hard! You only need to consider these 3 specs: 👇

  • Pitch: The distance between 3 consecutive rivets divided by 2.
  • Gauge: The width of the drive links.
  • Drive Link count: The number of drive links in your chain.
Infographic that explains pitch, gauge, and drive links count of a chainsaw chain.

These specks are usually written on the package (check the image for example 👇). If you can’t find it, ask the dealer or head to the manufacturer’s website.

brand new chainsaw chain

Once you have the numbers, match them with the pitch, gauge, and drive link count written on your bar.

chainsaw bar required pitch, gauge, and drive links written on it.

If one of the numbers don’t match, then you’re holding the wrong chain!

What's the Solution Then?

If you’ve got the wrong size chain, there’s NO other way but to replace it!

Go to your nearest dealer store, or order it online. But this time, make make no mistake with the specs! (For more info: Are Chainsaw Chains Universal?)

Your Chain Sprocket is Worn Out

A worn-out sprocket can also prevent your chain from tightening.

But how?

Over time, chainsaw chain sprockets (also known as “drive sprockets“) wear out and develop deep grooves in the teeth. (Here’s an example of that: 👇)

Difference between a brand new and a worn-out drive sprocket.

This happens because the chain’s rubbing against the sprocket, which makes things get all hot and bothered.

Also, having the chain tension way too tight or super loose can play a part in the drama.

And when the sprocket teeth are worn down, the drive links won’t sit between the teeth. Rather, they’ll just slide right over the worn-down grooves and won’t let you tighten your chain!

How to Tell if a Chain Sprocket is Worn Out?

  • Check for visual signs of wear: Take of the clutch clutch cover and check if any of the sprocket teeth are worn down or if there are deep grooves. (A little bit of wear is normal, but if the grooves are 5-6 mm deep, you have a problem!)
checking sprocket for wear and tear
  • Your chain keeps coming off: If it keeps slipping off the bar, it’s a tell-tale sign that your chain sprocket is worn-out.
  • Your chain doesn’t stay tight: A worn-out sprocket won’t let your chain stay tight for longer! (Here’re 7 tips to keep your chain tight for longer)
  • You hear unusual noise: If you hear unusual scraping and grinding noises when the chain is in motion, that’s another sign that your sprocket is worn out.

How Do You Fix It?

If your chain sprocket has serious wear marks and you’re already dealing with issues, my recommendation is to replace it ASAP!

Otherwise, it could damage your chainsaw and put you in a dangerous situation.

Wanna to learn more? 

Check this article out where I’ve discussed when to replace the chain sprocket in great detail.

Your Chain Brake is Probably Engaged

This might sound a bit SILLY, but is often the case!

The chain brake is designed to stop the chain from spinning in case of a kickback.

When the chain brake is engaged, it can prevent the chain from tightening when you try to adjust the tension. So, check if your chain brake is engaged or not!

Chainsaw chain brake

How to Tell if Your Chain Brake is Engaged?

Well, it’s not that hard! You can guess it by looking at it –

  • if it’s in an upright position, then the brake is engaged.
  • If it’s tilted back, then it’s not engaged.
Engaged vs disengaged chainsaw chain brake.

What if Your Chain Brake is Engaged?

If your chain brake is engaged, then all you need to do is – grab and pull it back.

That’s all!

You will hear a CLICK sound when you release the chain brake – this sound indicates that it’s disengaged.

how to release chainsaw chain brake

GoodBye Words!

It’s time to say GOODBYE!

I hope that this article has been helpful in troubleshooting your chainsaw chain that won’t tighten.

If you still can’t get your chainsaw chain nice & tight, it’s probably because you’re not doing it right. Check out this article where I break down the proper way to tighten a chainsaw chain!

Happy sawing!

Samuel Anali

Hey there! My name is Sam, and I'm the NERD behind this site. I'm an avid chainsaw enthusiast, and I've been tinkering with them since I was 17 (it's almost 20 years now!).

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