Tunedpipe has a good point. Once you remove the sparkplug you can use a chart like this one below to check the heat that it was running at. A Lean tune should run hotter. Check your manual it might help you troubleshoot. I also dont own a 1/5 gas so my experience is very limited
does the engine turning over when you use the pull start? as tunedpipe said have you tried a new spark plus if so then youll probably need a new coil. I dont understand what you mean by loose. do you mean low compression ? i dont know about those 2 strokes but other 4 and 2 stroke engines have a...