Why Replace the gray fuel lines?
Because they are cheap, and disintegrating into the fuel system. If one carb gets more crud than the other, then one runs lean. Sometimes this can contribute to a ruined jug, and the need for a top end job.
They look FINE on the outside, but the INSIDE green slime/glue/crud is simply horrible.
I did not believe it at first, until I took mine apart. It is for real.
You will need 25 ft of good fuel line, and about 15 stainless steel clamps.
It is easy, if you do ONE at a time.
NAte