Hi mate, glad it helped... however, now that you say it was hard to pull again as soon as you put the spark plug back I'm thinking 2 possible things....
1. Did you pull it fast and if so did any petrol spit out the hole where the spark plug goes? if not then you need to do that, a few times, very fast, doing this empties the combustion chamber, also leave the spark p[lug out over night to allow any excess fuel to evaporate, also did you check the oil? if so was it over filled and come running out really thin? This would indiscate the oil is full of fuel... do an oil change and top up to correct level....
2. If the above is all in order then you may need your valves setting or you may even have a sticky valve.... let me know if you think this is the cause