Does not sound good, could be as I first suggested, may be an issue with the crank.Ricko wrote:Despite the rebuild I've still got doubts about how hard it is to turn over,
These engines do turn over quite easily, and in no way should it be hard to pull them over, kids can start them.
Did you clean the surface of the points, they can look clean but can be coated with corrosion, bit of fine wet and dry and clean with a bit of card.
I would strip the crankcase, remove cylinder (only 2 bolts, head can stay on), reassemble crankcase and tighten it up, crank should turn easily with thumb and forefinger, the weight of the piston and conrod should rotate the crank easily.
You have had it apart before, so you can get it apart again easily, should take way less than an hour.
Don't give up, you will suss it out.