Electric chainsaw repair (and an "oops" moment)

[PStechPaul]

John was going to use the Echo 56V battery powered chainsaw yesterday, and said it "wouldn't start". OK, I guess John (the One Man Wrecking Crew) broke something else. I verified that the battery was fully charged to 57 VDC, but the chainsaw did nothing when I pulled the trigger. I found that the chain would not move (which should have been a clue about the problem), but I figured it must be something bad, so I removed the chain and the cover which exposed the brake and drive mechanism. Then I noticed that the brake was engaged. Hooray, a simple fix! But it was not to be. When I operated the handle to release the brake - SPROING! The spring popped out of it's place, and disappeared. Fortunately I found it, but it was too difficult to squeeze it back where it belonged. After disassembling part of the activation mechanism I was able to push the mechanism far enough out of the way to force the spring into place, but then the mechanism would not go back together. So now I need to figure out how to get the spring into place. It might be possible to compress the spring in a vise and then use some wire to hold it compressed while I put it back in place.

Here I have pulled the brake out of it's receptacle to try to allow the mechanism to retract further:



This shows the recess where the spring goes. If I remove the activation cam mechanism the spring plunger will move further to the right, and I could get the spring mounted, but then the cam mechanism would not go back together:


Brake released position:


Brake engaged position

[PStechPaul]

I just noticed that, although I had added four tags, the post shows "Tags: None". However, if I click on "Tags", it shows the tags I had entered, and when I click "Save" they are shown. But they don't "stick".

[Lew Hartswick]

I used a 21 inch chain saw for years without a brake. They are nothing but trouble.
...lew...

[eKretz]

Maybe not so useless on an electric saw. On at least some of those the brake is the only thing keeping the saw from going full throttle if the trigger should be depressed. Generally they do not have any interlock like a gas saw trigger, and they will go full blast at the press of the trigger since there's no requirement for the engine to be running... The battery could probably be removed every time the saw was shut down but that would be a pain.

[Mike279]

A large flat bladed screwdriver inserted into the end of the spring is how some springs are compressed and somewhat controlled in videos of chain brake spring installs.

[PStechPaul]

Like this?

Or this:

(About 3:20)

Thanks for the tips

[wmgeorge]

The only chain saw that I ever left the brake on was my Stihl which I still use. The cheaper saws had nothing but trouble with the brake.

[boslab]

Chainsaw and oops should never be written!
Mark