[Honda-C70] 1981 Passport C70 not running

  Hello:My C70 was running 3-days ago.I went to start it the next day and it would'nt start,I've checked the gas line,it's getting gas,I've checked the spark,at the plug,it's getting a dark blue spark.I took the plug out,dried it off,put it back in,it started.One hour later I tried to start it,