The carb on my stock qt50 has had too much tinkering with before i got it .i have decided to either buy new stock replacement or go with something that might work better ..i have seen some posts about running 15:15 sha on these .question is to those that have swaped if it is basicly plug and play or do i need to get other parts to make the change over before i order one..thanks in advance for any info on this