5lblmbn2009 is correct the fuel from the A/P is not reduced in volume having the stream split allows the fuel to be atomized better which means you get a better and more efficient burn during acceleration and that gives better response and a cleaner burn. It makes for a much crisper response while accelerating.full carburetor disassembly is required. takes a taper proof t-15? i think its 15... might need to lightly tap the top of the nozzle that is in there to get it out. other one just gets installed in same hole and you will have to line it up somewhat... not too difficult.