Chainsaw Repair

Last one I tuned I noticed the H screw was really touchy minute adjustment would radically alter the rpm's.  I'm talking about 1500-2000 rpm's.  This one is for my grandson (NIB) saw 2008 ym.  It is pig rich @ 12,200 slight I mean slight turn 14,500.  He nor his Dad know anything about tuning a saw and I don't want to give it to him pig rich.  What's up with these carbs I remember the last one was real sensitive too.
 I remember Randy (MM) quit porting them because of carb problems anybody know what the prob. was or is it the same as mine.
Shep

If it's the same carb as put out on the 5105 & 510 (+others in older series) zama c1q dm14 it could be the troublesome little valves inside. I tried 3 used ones on a 5105 before Killian red Leo got me in touch with a gentleman selling them new for a good price....zama wont sell just the little valves.....