Neil -- your engine should be run rich, but not "slobbering" rich. When you get it going, open the throttle fully, then slowly close the needle valve and you will hear the engine note start to rise sharply. Stop at that point and back it off until the note starts to drop. Run it like that for 2 - 3 min then shut the motor off & let it cool. Keep doing that until you have run through a couple of tanks of fuel & you will then be good to go.

ABC engines need to be broken in at a rich 2-cycle, & if you have it too rich you will indeed damage it. If you have it too lean you will damage it even faster. Your best bet is to find experienced help.