It is a pity because it runs so well it is just every now and then it decides it won't turn over, then the next pull it is fine and will start. I will probably just put it back in the shed again for a few more years
I just go by the 3 rules for a motor to work correctly.
1 Spark / 2 Fuel / 3 mechanical condition of all motor parts .
If the motor won't turn over when starting and it's not the coil rubbing on the flywheel and the motor is not seized then it would be a compression issue,this type of motor you can rule out fuel leaking into the cylinder but if the guides or rings are not within the correct specification then oil can leak into the cylinder causing it to hydraulic lock when starting but if that was the case on start up the engine will blow smoke for a several seconds.
These motors have a Automatic Compression Release mechanism on the camshaft that holds the valve open on starting if this is malfunctioning compression is not released causing the engine to lock up when starting.
Hi Norm, I would check the easiest things first ,like the flywheel is not slightly loose and moving on the cranks keyway or sometimes I've had bad spark plugs that cause backfiring and it doesn't take much time to change the coil just in case that has an intermittent problem .
It's just that you mentioned the starter handle being ripped out of your hand with the lighter blade assembly, that's not a compression issue it's usually advanced spark or loose (slipping) blade plate on the crank or slipping crank blade plate boss.
Hi Max, the original blade was one of the 300 gram Sprinter ones and they can't cant slip because the blade is located on lugs. When it decided to grab it would nearly pull my fingers off Good point about the coil I will give that a try but I don't think it is a timing issue
Hi Max, I think you nailed it, I changed the coil and I started it about 4 times and it didn't kick back but it is still heavy to pull, like it is high in compression. Certainly not suitable for a woman to start, it feels as heavy as some of those 5hp Quantams. I will try it a few times tomorrow and let you know