RE: Question for you Enya Guru's
The 15% fuel is fine. They will also run fine though a little less power on FAI fuel (no nitro).
Each side of the exhaust outlet there should be a hole where once a rotary exhaust baffle lived but is no longer needed with the advent of idle bar glow plugs and mufflers. The baffle was rotated by linkage from the second arm on the throttle.
Again, I'm not positive that the II and III were on the case but it seems to me they were. And, I'm not positive but I don't recall that the III having an exhaust baffle.