RE: How well did your YS run after sending it in for service?
Myself I feel a phone call is in order to YS and talk with Richard. What is the engine doing or should I say not doing , besides not running right.
The 91 FZ I sent in runs like a dream now after the new piston was added,thats really all I can go by myself all of my other repairs I did myself with the help of central hobbyies or YS for parts.
The engine ran ok for 5 flights then started acting up ,so I would think it had to run fine when it was bench tested at YS. A prob that shows up that soon does not look to good I have to admit but I think a phone call can get it straigtened out .The trouble is theres shipping and down time again, and if your friend is like me I didn't buy a engine to ship through the mail I bought it to fly a plane.
Let us know if theres anything we can do to help your bud out, i'm sure that whatever the engine is doing isn't the frist problem of that sort and maybe can be diagnosed right here.