How does the 100LL run at 14-1?Lucky you are somewhere high enough altitude that it will burn at all.
Another one of my Grandfather's friends had an old steering wheel rigged someway to engage the pawls on the flywheel in place of the JD hand crank. I guess to get a better grip than on the flywheel. Pretty sure you would want the spark to fire a little bit after TDC to hand start it, like starting a Model T or Model A Ford.
AvGas vaporizes so much easier, more completely and at lower temperature, than modern pump gas, particularly in a low compression engine like that, is likely why it runs better.