Stihl MS 311 miss

[Slime]

I am working on a Stihl MS 311 that had no spark. The ignition coil was shot, and owner wanted to try an aftermarket coil. I installed it, and the saw ran fine.....for awhile. Then it started to miss. At medium speed (maybe 5K to 10K rpms) it runs fine. The final squeeze of the trigger puts it up to 12,500rpm, but then it starts to miss. There is maybe a half second to a second between misses. Of course, I suspect a faulty coil, but before I replace it, any other suggestions?

 

[cookies]

try a new ngk plug, if still being weird get a used oem off flea bay. They are under 30 bucks and seem to last and last if the plug is changed annually

 

[Slime]

try a new ngk plug, if still being weird get a used oem off flea bay. They are under 30 bucks and seem to last and last if the plug is changed annually

Thanks, cookies. I will try that.