Update: New flywheel has fixed most problems. However, i have a new problem. Due to running with a cracked flywheel, the 'key slot' on the input shaft has deformed somewhat. Which means i cant the key in between the flywheel and the input shaft,(down the slot).
I substituted a piece of steel that fit the key slot, mower ran great for 20mins but now the steel has destructed somewhat and not holding the flywheel in the correct position. Probably too soft steel. So, what is the solution here? I will try and get a new key but i doubt i can find one...