I remember years ago I bought a new Enya 09 r/c (my first rc motor) and it wouldn't idle well, always cutting out because it was too rich. I tried unscrewing the idle mixture screw and the motor would run much better with the screw almost out to the last thread, so with a1mm drill bit I opened up the idle air intake hole (it was 0.7mm). This cured it completely, the mixture screw had to be screwed in to 1/2 way obscuring the intake and it gave me a sweet idle.
Must have been a "friday afternoon" engine



Taking a closer look at the carb, the body is just a piece of 1/2" aluminium stock bar [>:] I could make another body from 15mm bar, just plane the needle valve side down to 12mm to accept the original brass barrel , needle assy, throttle stop AND include an idle mixture screw !

[8D] I wonder if I made a few of these marketed as" CARB BODY AND IDLE AIR SCREW" and that used all the other original carb parts I could sell them for about $10