2 cycle engine question... FIXED!

Sounds as if you have been there and done that
I have several of the Echo pack Pack blowers a few have experienced similar symptoms - none have reed valves - a carb cleaning and exhaust service and they are back in service - very simple and reliable engines

" been running for a couple of years now without trouble until the last FEW MONTHS. It has developed a problem that it will run at low idle only. If you turn up the throttle it will stall out".

Check the exhaust system/port before tearing into any 2 stroke small engine. It could well be a fuel problem but you could also go around and around if it's carboned up.
Is there proper fuel oil ratio in tank?

Does it try to run, indicating it's getting some sort of spark?

Does it have a reasonably normal resistance when pulling the cord indicating that the cylinder/bore isn't toast?

Check exhaust port/muffler.

Proceed to next issues. If it's idling and you slightly choke it while trying to throttle it and it runs better, then it's probably lean.

Another issue with a lot of hand held equipment is fuel starvation because of rotted fuel lines. Bogging, low power, erratic rpm, poor full throttle performance.

BUT STILL No matter what you do to that piece of 2 stroke equipment is service the exhaust port so the customer isn't back in a month or two with poor performance.

Just about no matter how the customer describes his issue whether he wants a new bar and chain and check over on his saw, a new string head and check up on his trimmer or a fall inspection on his snow blower, you service the port and muffler.