Mark .... if it has compression and spark then, beyond something truly bizarre like the packing in your silencer collapsing and blocking the exhaust (even then you'd expect some flutter out of the easystart) .... my money would still be on timing as it should do something on easystart under those circumstances.... totally frustrating for you .... as above, I'll be interested to see what the problem is when you triumph over the cast-iron demon.
K