One line goes from the fuel tank to the carburetor and the other one goes to the primer.
The second line is the return line for the primer. It only sticks down into the tank about 1/2'.
The hard one to repace is the one with the fuel filter on the end. Here is some instructions on how to replace the line with th filter on it.
When we replace the fuel lines, we make sure that we have about 2 feet of line to work with. You don't try to put it in the same way it was at the factory.
The first thing that you do is make sure that you have the "CORECT" size line...this line must fit VERY snug through the hole in the tank as it has to seal against the tank so it doesn't leak.
Now, first take the 2 foot piece of line and split the line right down the middle and then slice off that half of the line leaving 1 1/2 foot of complete line with a 6" tail that is split wide open.
Take the end that is split and poke it into the small hole in the tank. Get a pair of forceps or needle nose pliers and reach through the gas cap hole and grab a hold of that line. Pull the line out of the cap hole until the entire split part is outside. Cut the split part off and install the fuel filter. Now grab other end of the line and pull on it until the filter is laying in the bottom of the tank. Measure how much of the remaining line is needed to reach the carburetor and cut off the extra. Then install the end of the line on the carb.
Now , that's not too hard is it? lol
The biggest mistake people make is that they don't buy a long enough piece of fuel line...or the don't get the right size of line.