ORIGINAL: Jeff-RCU
Matt, you are struggling with what every piped 2 stroke application struggles with. The change that occurs when the engine comes on and off the pipe. We sometimes have the mentalitiy that we need the maximum HP out of an engine, but what we really need is maximum throttleability (linear up and down). I''ve often thought the the thing to do is run a slightly bigger 2 stroke and put it on a muffler instead of a tuned pipe. I've run the OS1.40 on a muffler with very good results turning a 15.5 x12 4 blade prop.
Have run piped 2 strokes for 30+ years and I know their shortfalls. What I am saying is that carburetion in this engine when used in combination with a pipe, is just a bit off. The only reason I even mentioned it is to assure the guys who are running theirs and see the same issue, that they are not alone
I am simply trying to find the right combination of load, pipe length and carb settings to get it as good as possible. It may not be doable with the current carb and Walbro doesn't make any 3 needle carbs that I know of. Carburetor may need to be sleeved. BTW some of my IMAC friends who fly large DAs on cans have the same issues as I do at transition
Bottom line, Is it usable? Absolutely. The engine doesn't flame out as glow engines will. Can it be better? I think so. You have to understand what my point of view is...I am a perfectionist