“You could also check to make sure the cylinder sleeve is aligned properly in the crankcase”
I think this might be the likely culprit will try running it again in the morning.
“I would be surprised and amazed if a .15 with a 10-6 would do over 10,000 rpm.”
I’m just going by what the Davis Diesel performance chart is quoting, I would be happy to see 9000 rpm. Before the conversion it was turning a Kavan 8-4 nylon at 15500rpm.
We are at 6000 ft. elevation I am using a J-Tec baffle less manifold with a carbon fiber arrow shaft extension on the exhaust with a I.D. larger than stock exhaust.