Where do the fuel lines go? How do they get routed? Which line does what? Which line connects to the fuel filter? This video will answer those questions. Please like, share and subscribe.
How to tell the suction line vs the return lines on a 4-cycle weed eater, trimmer, blower or edger:

THE SUCTION LINE
1. Cover one of the ports with one of your fingers on the carburetor and press the primer bulb. If fuel comes out of the other port, then the port that you covered is the SUCTION line and this is where the suction line should connect that connects to the fuel filter in the gas tank

THE RETURN LINE
2. If gas is in the primer bulb and you cover a port on the carburetor and you press the primer bulb
and no gas comes out of the other port, then the port that you covered with your finger is the return line and this is where the return line should be connected that goes about an inch deep into the gas tank. This line DOES not connect to the fuel filter.

GENERAL WAY TO DETERMINE SUCTION VS RETURN LINE
Put some gas in the gas tank. Attach a fuel line to any of the ports on the carburetor and insert it into the gas tank. Press the primer bulb on the carburetor and if you see gas being sucked up into the carburetor, then you have connected the fuel line to the suction port on the carburetor. This is the line that should be inserted all the way down into the gas tank with the fuel filter on it.
+ If you connect the fuel line to a port on the carburetor and insert it into the gas tank and press the primer bulb and it shows fuel going from the carburetor back into the gas tank through that line, then you connected the fuel line to the return port. I hope this helps with proper routing of fuel lines on a 4-cycle weed eater, blower, trimmer or edger, etc.