Jonsered 670 won’t hold its tune

[JohnT34]

I bought this jonsered a year or so ago when it was traded at my local Husqvarna dealer
It’s a one owner saw that has never been used professionally. I even got the original manual with it. The guy that had it is around 80 years old and couldn’t start it any longer
I went through it top to bottom put a new meteor piston in it, did a base gasket delete
and tuned it
So it’s problem is that the H screw keeps opening when running making the saw way too rich
Anyone see this problem before and would changing the spring on the H screw resolve this



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[Justsaws]

You can try a new spring, knurling the threads, etc., chances are it is new carb time, especially if you plan on using the saw. The hole the screw threads into has likely been wallered out. If you order a new carb, try and get a new screw boot or do not install one. Once they hardened up it made things worse.

Fairly common on those saws.

 

[Leerod83]

What about a thread locker? I thought i read where they make one for high vibration.