Recoil spring question...I know not gun related

[CYanchycki]

So the dilema.

Partner 7000 chainsaw

The recoil spring broke about 4" back from the end. Cannot find it anymore as the saw is old. It is a beast for a 70cc saw.

For you guys that may know metal, do you think I can heat it to soften it to form a loop at the end? How about tempering after if it works? Heat again and a quick flash in water to temper?

Your thoughts?

Saw runs great and eats thru trees but no good without the recoil to start.

Calvin

 

[jackie schmidt]

So the dilema.

Partner 7000 chainsaw

The recoil spring broke about 4" back from the end. Cannot find it anymore as the saw is old. It is a beast for a 70cc saw.

For you guys that may know metal, do you think I can heat it to soften it to form a loop at the end? How about tempering after if it works? Heat again and a quick flash in water to temper?

Your thoughts?

Saw runs great and eats thru trees but no good without the recoil to start.

Calvin

https://springsteelstock.co.uk/hardening-and-tempering/
Calvin, what you can do is heat the end that you want to form the loop on to a red. That should allow you to form it around a radius mandrel of the proper curl.
After it is formed, continue heating to a orange color, and quench in oil. This will re hardened it.
But since that might be too brittle, re heat that end to about 500 degrees again and let it air cool. That will possibly bring some amount of ductility back so the curled end just doesn’t snap off.

https://www.engineeringtoolbox.com/tempering-colors-steel-d_1530.html

Keep in mind, spring steels have by their nature a rather high carbon content. Once hardened, it can sometimes be difficult to determine the exact properties without very sophisticated procedures.

 

[John S]

https://www.ebay.com/b/Partner-Chainsaw-Parts-Accessories/85915/bn_7892812

This page has a complete starter assembly for $25

 

[Dans40X]

Op,
Any small engine repair shop should be capable of cross referencing a recoil spring.

Take the complete recoil starter with you to change the rope also.

 

[CYanchycki]

Thanks guys for your input.

Jackie, i was able to heat the spring and form the small loop on the end. Then heated again and tempered it in oil like you suggested. We will see how long it lasts. I had to form it a bit but worked the spring carefully by hand. Put the beast together, dumped the old fuel, filled with fresh premix, some octane boost, and that beast came to life.

That saw is intimidating. I could not imagine anything with a bigger engine on a saw.

John, i did find what you mentioned from Ebay. Not sire why I did not see it. I ordered one and it supposedly has shipped. If and when it comes, there is a spare.

Thanks again

 

[Dans40X]

OP,
Run a 125cc power head w/ 72" Ti bar felling saw & the 70cc power heads are arborist / limbing saws.