The TsuMara 20" bar is 3/8 pitch and has both 050 + 058 markings on it. It is well oiled, nothing's pinched, nose sprocket turns easily. Mind you I have run about five tanks of fuel with no problems. Makita service center has it, I will post what this baffling problem is when I find out.
After cutting one 15' log, I restarted it throttle won't spin chain, put the chain on a log & pushed it along the bark thinking debris had clogged underneath the cover, nope nada. The clutch drum seemed a bit floppy, like not seated right. Spacer, needle bearing are all there. Took it off & on a couple times to watch the clutch expand, which it does.
There are two "ears / tabs" on the clutch drum, and also two more similar "ears" behind the clutch, not sure of there purpose.