the low screw (nearest the engine) controls the low rpm by turning it in slightly, it will raise the low rpms. ("lean" is less fuel and higher temp, as "rich" is more fuel and is cooler, in is less, out is more)
the high screw (nearest the airbox) again controls the high rpm. turn in to increase the max rpm.
now the leaner the you run ( thats turning the screws in, thus starving the engine of fuel) will make the engine get hotter! and turned out will make it run cooler.
some tracks with long straight will require you to have the hi screw turned out (richer) so that when the kart is at max rpm for a sustained period you dont overheat and cook your engine!
on the opposite end some tracks you can lean off the hi screw to run a higher rpm ( because you need to get to high rpm quickly but not a long period, but you will have to richen the lower screw so that when your lad brakes and the engine drop to low rpm it doesnt overheat at this point. (if the low screw is running richer it will cool the engine). this however will affect the lowend acceleration, so your lad has to be able to carry good corner speed. getting the set up is an art and i after a year of racing am only just starting to get the hang of it now!
get a data logger like a mychron so you can montior what the engine is doing. ie revs and temp. it will show you at what point your engine is reaching it highest temp and thus you will be able to make an adjustment at either high rpm or low rpm.
also another consideration is the gearing which affects the rpms so this has to be taken into consideration.
its not as easy as just having one setting and then away you go, but it is good to have a base setting that you can go back to if you get all confused. ive marked my carbs with a base setting so i can always find half a good setting to start from.
hope this helps a bit
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cadet comer carb.... by 'cadetdad66' (23 Apr 2009 @ 11:26)
