Appears to be a Mini Mac 1 with the removeable starter, much easier to work on. On the Mini Mac 6 (non-removeable starter) you have to align the fins in the flywheel with the starter "clutch" in order to slip the engine out of the housing and back in again. Most of the older saws will have the Walbro MDC carburetors that can be troublesome. The check valve is a thin little rubber disc and replacing them requires drilling and tapping the plug to be able to pull it out. The later Zama equipped saws seemed to be more dependable and even better performers.
I do get frustrated working on them at times when things don't go as planned, usually something I did wrong or overlooked, but they are no worse to work on than any other top handle models. The SP40 and PM510 were better in that you could remove the carburetor to work on it without dismantling the entire saw; Tillotson HU models that were also more dependable and more familiar to most folks.
I once had to work on my son in law's 020 AVP, that was frustrating...some of the "Italian McCulloch" saws are pretty challenging as well.
Mark