Hi Carl,
From the sounds of it, there could be a full range of issues with it! It seems though that these alternate-firing 2cyl./2 stroke machines just run rough like that UNTIL you put a load on 'em. All the Mercs I've seen run similarly, especially the DA-211s. I could retard the timing some and smooth it out, but the power would also be retarded. Retarded timing plus retarded power and toss in a retarded operator and the wood will be free of worries.
I could be wrong on this saw as yesterday is the first time I've ever been around one running,
(a SuperTwin). I'm gonna fiddle with it a lot more but I'm always happy to try ideas of others.
By the way, there's a major GTG being planned for a few miles south of Richmond for March 31.
We're expecting you and Ginger to be there and at Halifax Heritage Fest. (first Sat. in May)
Igpoe