Very stiff drive sprocket

[thesheep]

I'm not actually a tree surgeon, just someone who has to cut logs occasionally but hopefully it's OK to post this question.

 

I have a small Makita electric chainsaw that I've had for a few years, pretty light use.

 

I went to sharpen the chain yesterday and found that I couldn't turn the chain by hand. Taking the bar off, I found that the drive sprocket is very stiff: I can just about turn it using a pair of pliers but not by hand.

 

The electric motor still turns the chain OK. Although I have to say it doesn't seem to be cutting as well as it used to, even with a sharp chain.

 

Should I have a go at taking it apart and seeing if there is something I can lubricate inside and how easy is that for a reasonably competent DIYer? Is there anything else to try? Thanks.

[Dan Maynard]

3 hours ago, thesheep said:

hopefully it's OK to post this question.

You can always ask, whether you get a sensible answer.....

 

I have Makita top handle saws, the sprocket comes off easily. It's not a clutch drum as on a petrol saw but there's a brake drum and band which can all be stripped out and cleaned, if you've never done this it is probably jammed up with sawdust. Think you just need a PZ2 screwdriver.

 

Taking the brake spring out was a bit more annoying but still possible. Have a careful look at the parts diagrams you can find online to see the bits.

[GarethM]

Does it turn and feel like it's ratcheting, probably a failed bearing either at the drive side or the end of the drive motor.

[monkeybusiness]

How does the chain brake work? Is it automatically on when not cutting?

[pleasant]

26 minutes ago, monkeybusiness said:

How does the chain brake work? Is it automatically on when not cutting?

Most mains electric or battery chainsaws have a cut out switch rather than a traditional chainbrake as you will very quickly burn out the motor and strip nylon drive gears if a brake band was used with power still going to the motor with it still switched on. Once the brake lever is activated it cuts the power 

Edited November 11, 2023 by pleasant

[Dan Maynard]

Just reading this again it doesn't say battery or mains in the original post.

 

My battery saw has a brake with a band and spring, and a cutout switch operated by the front handle.