It is very difficult to try and repair any of these sort of machines, they are very fiddly, frustrating and time consuming and the only satisfaction is in getting them running, certainly not something you can make any money on
Hmmm I don't have any problems fixing them as long as they haven't been straight gas. Maybe it is that I just work on a lot handheld 2 cycles.
It is the 4 cycle Mtd line that are a waste of time to look at as they are usually failing because of oiling problems. Now the Stihl 4 mix system are very good and I repair several of them every year. I hear that Honda produces a 4 cycle handheld model but I haven't seen any of them in the shop so I can't say one way or the other about them.