Can someone tell me how to tune the low speed setting on an engine properly. I am new to rc cars and I find this setting very hard to get right.

Thanks in advance

let the engine idle for about 10-15 seconds. Then jab the throttle, if it chokes and a plume of smoke comes out it is too rich...if it has little smoke and revs up it may be too lean. It should idle good, set the carb idle screw at about 2-5mm. Then adjust the low speed needle, if it idles too quickly and it revs up buy itself, then it is too lean, if the idle is too low and dies, then lean it just a bit, go by 1/8 increments then fine tune with 1/16 increments.

do the pinch test to check. Pinch the fuel line just before the carb, If it dies instantly, it's too lean. If it takes 4 or more seconds and reves up before it dies, it's too rich. It should die with in 2 second and not rev up