color doesnt really mean anything

THe nexstar has a somwhat wierd system of fueling as it is a 2 lin system i myself use a 2 line (one to the carb one to the exaust) you have easy accese to the carb line

ok so from the tank you will have 3 tubes

tube #1 has what we call a clunk on it it goes into the tank andhas this wight on the end to keep it in lowest part of the tank and thus always giving the engine fuel this line goes to the high speed needle valve (carb line)

tube#2 is your vent line this one comes from the muffler it over back pressure to the tank to help feed the engine fuel. This line connects to the tank you will will find a little tube that goes to the top of the tank this is your vernt line

tube #3 is your fueling line this is actually not nessecary on a nexstar because you can just as easly (actually easier in my opinoin) remove the line form the needl;e and fuel that way. this tube is the one with the small "cap" on it

I hope this helps