Back about 6 months ago I was looking for either a good PM55 cylinder,or a PM55 parts saw that was reasonably priced.I just bought a used cylinder that seems to be in good condition.I also have seen PM55 saws coming up like crazy on feebay.
I was out cutting with my first PM55 last week & it started making a dinging sound when I'd pull it over.From a previous experience I had with a RH 10-10 I found the noise was an indicator that the flywheel nut was loose.I pulled the saw apart on Sun.to find the FW nut was almost completely off the crank.I've never had the FW off & I ran that saw extensively last yr.& never had a problem.What would cause the nut to come loose that quickly?