G'day Norm and Tyler,
trying to pull start it it kicks hard and lifts it up in the air, pretty much the same as a mower with no blade carrier.
I would usually disconnect the spark plug lead and pull the starter handle a few times, this will tell you if it's kicking back from high
compression and not enough rotating mass or if the plug is firing before top dead centre and pulling the starter handle out
of your hand ,when it's a compression problem with not enough rotating mass the handle just stops when trying to start but
advanced timing will pull the starter rope back a lot more.
If it's more of a spark problem so the starter handle is not pulling out of your hand with the plug lead off then I would
gap the coil further away from the flywheel magnets ,this will retard the spark a little so it's not trying to turn backwards
when firing.
I've had quite a few newish motors kick back and when I check the gap on the coil to the magnets the factory has
assembled the coil too close to the magnets and it's made the starting a lot better after increasing the gap.
On some engines it may be worth putting a thicker cylinder base gasket on to reduce the compression but this will
effect port timing.
Cheers
Max.