Kevin,

With my Moki's tuned slightly rich on the high end and "about right" on the low end my engines have a slight "gurgle" in the 25-35% power band. The only time I use that power setting is on my initial entry to downwind for landing with my Christen Eagle, so I just live with it since I spend so little time at that setting.

My high end power settings with a narrow blade APC 20x8 prop are 7200 RPM (set slightly rich). I don’t remember my idle RPM’s, but they are as low as you can get and still be smooth; and they do so reliably with just the slightest hesitation before making a rapid transition to full power.

I initially setup my first Moki using 5/32” fuel tubing made by Dubro, but later switched to a smaller fuel tubing (Large) with no ill effects. My friend is also using the same brand of Large fuel tubing on his Moki (inverted setup on a Mustang), and that engine also runs great. I don’t know if the I.D. of fuel tubing is standardized but we are using Prather fuel tubing, which I don’t think is available anymore.

The only negative that I have found with my Moki’s is that the engines want make an immediate transition from low power to idle power while in flight (on base leg turning final approach) unless the idle speed on the ground is set up as low as possible. That caused me to have to “go around” several times and forced me to set up my approaches where I had to come in higher and pull the throttle to idle further out. After getting the idle set to a lower RPM this has not been a problem, which is good since I prefer to fly my final approach with a touch of power and need the engine to transition to idle on demand. I do suspect that I could adjust the idle mixture just a hair more and maybe get rid of this problem, to the extent that the idle speed could be increased just slightly, but I have not tried to do so. An extremely low idle is usually not needed for a high drag biplane or monoplane with a big round cowling, but could be helpful on a slick airframe.

I am very satisfied with my Moki’s and they have never flamed out and turned my models into high wing loaded gliders. I could tinker with the needle settings more but just haven’t done so since these Moki’s have been dependable as is.

I hope that you can learn something from my engine setups to help get your Moki running to your satisfaction. Keep us posted.

Mike