If the pull starter is hard to pull this means that the engine is flooded (there is too much fuel in the combustion chamber). At this point don’t pull the recoil starter any more – doing so will damage the recoil spring. or break the pull cord.
Solution : Remove the glow plug from the heat sink head and turn the car upside down. Now pull the recoil starter a few times to expell the excess fuel out of the combustion chamber. Replace the glow plug and start again.