eey pepe,
what color does your spark have ,it should be blue/white and you must hear the spark too,if you kick it over.
sounds like: tiktik but then faster
also ,how good does it start with the weak spark?
it should fire up less easy then with a fresh good spark.
got fresh plug installed also?
and the cap and wire still intact and good?
if so it,s probably in the ignitioncoil,it could be worn and need ro be re-winded.