engine trouble
As per D.J.s post ... !
All I can suggest is fuel and spark - the rest is just rattle, clanky stuff.
Pull the spark plug, reconnect the lead and touch its body to the cylinder head so you can see any spark, crank the engine and you should see the spark, if not, check the gap- it should be maybe 30 thou (check your manual). If the gap is reasonable and there is no spark then you have either a knackered spark plug, a broken lead or a lack of HT. Is there a 'KILL' switch built into the throttle ?
While the plug is out try putting your thumb over the hole it came from and turn the engine slowly, you should feel a good suction and a good compression, if not, you need to consider refurbishing the engine - piston rings and head gasket as a minimum; cylinder bore circularity (the bore wears oval eventually - "scrap the engine" time :? ) and crank shaft and conrod bearings need to show no 'slop', nice and snug.
You say you checked the carb - is that just visual ?
Could the jet in the carb be blocked, a small jet only takes a small amount of fluff/dirt to block it - strip the carb and wash the bits in petrol (keep Tails away :wink: ) - try to back-wash the jet to dislodge the crap.
Clean any fuel filter or better still, replace it. Wash the fuel line and tank, it's pointless cleaning the carb just to clog it again.
I regularly use petrol stored in a can (or left in the mower) from the previous year with no problems but some say never use old fuel :shock: (seems like a waste to me).
Failing that, buy a new mower :wink:
As an afterthought --- when ( :!: ) you get it running again --- after you have finished mowing, let the engine cool down and pull the spark plug again, look at its colour, this tells you if it is running too rich or too lean.
Look at **broken link removed**
or
http://www.nightrider.com/biketech/spkplghnbook.htm#We for a guide to colours. I often find two-strokes run best when they are just a bit rich, try to get them "spot-on" and they can be difficult to start when cold, I know this contradicts the "official" information but it seems to hold true for me.