My first YS was a 53 FZ that had a factory fault. It passed through two previous owners who failed to find the issue. My finding it was almost an accident. It had a TINY hole in the carb under the throttle plate so it would suck air. The engine was years out of warrenty so I fixed it with a little JB Weld. It is the sweetest engine I've ever had. It ran all summer long with only two adjustments to the high speed mix. ( three clicks each way) That was only necessary because of large temperature fluctuations. I've since purchased a second YS, an older but barely run, 120 NZ. I also ran flawlessly on the test stand. It awaits an airframe to stretch it's legs in. I intend to purchase more YS's as the need comes up.

Ken