tyrolean_marcus, There are a couple of things which i would check , but first some info is needed .
1) Has the plane/ engine been stored for a while (weeks or months)
2) Has the engine been off the airframe since last flown
3) How did the last flight go ,any sputtering in the air or unusual transition concerns prior to this most recent event.

I would first verify the ground strap is firmly connected to engine or sparkplug
I would also check the screen inside the carb. (these tend to plug up ), at the same time verify that the carb is not loose (but do not overtighten and damage the
gaskets between the carb and insulator and the insulator and cylinder)
also check the gap between the pick up sensor and the magnet ( shouldnt be more than about .020 -.030 )
Make sure your muffler is tight also , these work loose and can cause some performance issues
Good luck , If all else fails call Gary at Brison