The engine ran perfectly until one day on the first start it wouldn't start. Head pressure in the tank was good - I used the Fourmost check valve in the UCD. It seemed like I ran my electric starter forever and continued to check the tank pressure whenever I stopped crankin'. When I did get it started, after much fiddiling (removed cowl, fuel filter, replaced glow plug) it wouldn't accelerate past mid throttle. It was always too lean. I guess the Cline wasn't allowing enough fuel through it. I removed the Cline, readjusted needles and flew many uneventful 3D flights. I haven't replaced the Cline yet and probably won't. I wonder, can you buy the diaphragm? I fly the UCD46 with an inverted Surpass .70 (my winter flyer on skis) and deal with the flooding issue. Engine/plane combo works great for me....although the Saito 100 would really be awesome in the little UCD.