I now have the engine assembled and mounted on the bench for test running.
However, it will not run. It will fire and sometimes run for a second or so. But won't keep running.
This behavior seems to suggest loss of crankcase compression. However, the front seal is new and is doubled up with the front bearing seal. The two halves of the case were joined up with "three bond" sealant. I also applied this sealant to both sides of the cylinder to crankcase gasket.
I am wondering if the next step is to do a crankcase pressure or vacuum test.
Any suggestions?

Also, I might have to consider a starter for this engine as my right arm is getting a bit painful from swinging the prop!

I'll post a picture later when the site decides to respond in "Go Advanced"!