I  took out my MTD 4.5 hp two stroke blower to clean up after  the small storm (4-6 inches)  we got hear in MA after the blizzard.    The blower started on the first pull.  I let it warm up a bit on choke then moved it off choke and started clearing the snow.  when the auger was engaged it was running OK  but when the motor was idling it felt like it was going to stall.   I kept the auger engaged and just as I made the last pass  it slowly   lost power and stalled out.  I could get it to restart?   .
I used echo brand oil   mixed 50:1 with new gas.    I noticed while running the machine ,it did back  fire with a spark shooting out of the muffler . this happened a few times.
Also I had lost the rubber disc that covers the sparkplug boot.   I noticed small sparks jumping from the boot to the edge of the cover .   perhaps that caused the Problem?
any thoughts would be a great help.
thanks
John
Scotts 21" self propelled  mower
MTD  4.5 HP single stage snow thrower
Snapper 3 HP single stage snow thrower
Yardman 5HP two stage snowblower