Finally figured it out.

The off and on rain has put a stop to my flying. I've been looking at the engine I got off a plane from the pawn shop for quite a while now. It's an OS .46 FXi r/c engine. Ball bearings and larger all around than the .46LA's I've been using. The hole for the carb. is 9/16 while the LA is 3/8 so getting a venturi for it is a problem, until today. Just for grins I removed the carb. and tried fitting K&S tubing into it. As luck would have it the 1/2 i.d. tube slipped right in with a snug fit. I took a 1/2 nylon spacer from the Dorman racks at Tractor Supply and that fit the tube really nice. The spacer had a 1/4 inch through hole so I drilled it out to .300 and cut one end at an angle for a smoother in flow of air. Then I drilled through the engine block and tubing and nylon spacer for the spray bar. The fuel exit hole wasn't centered so I drilled a new hole and soldered shut the original. Then I tested it behind the garage and it ran very well. I don't have any plane that will accept this engine as it's wider and a half inch longer so I got out some paper and started drawing another P-39 fuselage. Trike gear and flat colors what could go wrong. Time will tell.