My .19 VI is cranky also. It's anything but a "one flip" engine but it may be my clumsiness in determining an initial needle setting. I can't wait to use up all my 25% lube break-in fuel and really let it eat on 20% with 5% nitro. I'm breaking-in on an R/C carb but have proper C/L venturis and spray bar. I'll keep your recommendation of orienting the spraybar discharge toward the rear of the venturi on the C/L spray bar. I noticed that the threaded R/C spray bar discharge on my new .09 is located in the dead center of the venturi. Mine is set up with the discharge flush to the outside edge of the venturi - my doing. I will attempt a run with the discharge in the center. I'm going to experiment also. I noticed that my .40 R/C carb has a small discharge tube depositing in or near the center of the venturi. I have never seen a carb (Weber, Holly, Stromberg, Tillotson, Zenith, Mikuni, etc.) that didn't have a discharge like my Enya .40. I have copper tubing - .062 OD, .032 ID - that I want to solder into the spraybar orfice on the R/C discharge with the dicharge end of the copper tube filed to a 45 degree angle. Of course the 45 degree discharge would be oriented to the down stream of the incoming air charge. I've got to believe that this arrangement would lead to less obstruction of the cross sectional venturi area and improve fuel atomization. By comparison, the discharge tube on my Enya .40 is .063" ID. .19 = .032", .40 = .063". I don't think a .032" discharge on the .19 will starve the engine at full throttle. Anyway, it will cost me nothing to do the modification and nothing to undo it.

I have no idea what my plugs are on my newly acquired Enyas. I assume, at present, they are Enya #3s. I'll order some new #3s from Enya and compare.

I'm breaking-in on a light 7 x 6 APC prop. Wow, this little devil will pull from a 9 x 6 to a 10 x 4? Torquey little engine or what! Top Flight recommends a max of 9 x 4. I guess I have a-lot to learn. Keep posting please.

Best regards,
Bill

Later: I wish to correct myself. The fuel discharge tube in the venturi of the average carburetor is at a 45 degree angle to the incoming air flow and the 45 degree bevel cut on the end is parallel to to air flow. Mikuni carbs main discharge is circular, perpendicular to the incoming air charge and very close to the perimeter of the venturi. Moral - Don't shift into first gear until you have started your engine (brain). I'm still doin' what I said.