I have a Saito 100 that has about 18 gallons through it.
I haven't had any trouble with this engine in the two years I have owned it, until this weekend. Saturday was the first time I had the plane out since last October. I couldn't get a flight that I didn't have a dead stick landing. I spent a couple of hours Saturday adjusting the low speed needle, and walking out to get my plane after the 7 dead stick landings.
I went home pulled the engine and tank, re-did all the plumbing, cleaned up the engine and took the carburetor apart, and re-adjusted the valves. I didn't notice anything wrong other than the the gap at the valve stem a little wide, but nothing excessive (.005).
I took it out again today, and had the same trouble. After 12 dead stick flights, I finally noticed that the low speed needle was working its self in. I would start out with the low needle out 2 turns, and when I would check it after the dead stick landing the needle was only 1/2 turn open. The O-ring seemed to be tight on the needle, but maybe not tight enough. I plan to replace the o-ring and see if this fixes my leaning out at idle problem.
I am running an APC 15 X 6 prop, OS F plug, and Wildcat 20/20 fuel.
Have any of you had the low idle leaning out problem?
Any suggestions?

Greg