Do you still repair YS engines?
I have a YS Fz80s that will not idle. This is my 5th YS engine so I am somewhat familiar with it. I'm just not the kind to completely break down this engine. I have tried several different glow plugs, 10% and 15% nitro, different prop sizes, set the valve gaps, stock muffler and no muffler, several needle settings all the way out to 4 turns. Even at 3700 rpm it still loads up and dies.
I have put around 7 tanks of fuel through this engine and still can't get it to idle reliably.
I think there is something wrong. Maybe there is a clog somewhere.
Please direct me to someone who can look at this engine.

Thanks
Steve McCarthy