Stop the train!
The friction pads in these cheap engines rarely give anyone fits when the clutch is properly set up.
Ok, the actual clutch spring may be set a little on the soft side. Once again, chalk it up to cheap quality control in China.
Here's how to adjust it:
(Refer to the link to the parts blow up from Bicycle engines . com for identification of parts)
http://www.bicycle-engines.com/2stroke-parts-clutch-assembly-c-4_7.html
1. Remove clutch cable from release arm on the sprocket cover and from the cable stop on top of engine case (#35).
2. Remove the cable stop from the top of the case (#35). Unscrew the lock nut around the bottom of the cable stop first, enough to release it from locking the cable stop from turning. Unscrew the cable stop from the case.
3. Remove the sprocket cover being careful to get the bucking bar and bearing ball if they try to fall out (#25 and #24) ((they call the bucking bar a "cam pin" in this diagram))
4. Insert a medium sized yet strong flat bladed screwdriver down into the hole that the cable stop was screwed into. What you are trying to do is get the blade of the screwdriver down into one of the four slots cut into the outer edge of the threaded clutch spring adjusting nut (#16).
You will have to feel for it when it slips down into one of the slots.
It is not directly underneath the hole but a little closer to the clutch.
5. Once you feel it drop onto a slot, hold the screwdriver there or have an assistant hold it for you.
6. Use a socket on the sprocket nut to turn the nut, sprocket and shaft assembly 1 turn clockwise, the same direction you would turn the nut to tighten it.
1 turn should be plenty but a few are stupid loose from the factory and you may need to tighten it some more.
Do not overtighten it because doing so will cause the clutch to not release properly and/ or you risk snapping the pindle (#21)
It is better to sneak up on the correct setting than try to get it done on one operation.
I know it's a PITA but better safe than sorry, eh?
7. Reassemble the whole mess, taking the time to clean everything and put a blob of fresh grease inside the hollow sprocket shaft before reinstalling the bearing ball and bucking bar.
Please ask more questions if any of this seems a bit fuzzy.