I have a Featherlite gas weed-eater. The fuel lines were cracked and unusable. I purchased a repair kit that included the fuel filter. The line for the fuel to travel from the gas tank to the motor went on just fine. The return fuel line is smaller. I cannot push the line onto the motor's, ummm, male part. I have used oil to make it easier, I have also tried warming the end of the fuel line with a hair dryer. No luck. The INSIDE dimension of the fuel line that came in the repair kit is 5/64" and the recommended INSIDE dimension of the fuel line that was recommended on a YouTube says to use 6/32".
Is there a reason that drilling the return fuel hole in the fuel tank to match the other hole, using the same INSIDE diameter fuel line as the other one wouldn't work? The male parts on the weed-eater appear to be the same size.
Without watching the video, or addressing the repair, a caution: Drilling a gas tank has a good chance of igniting fumes even if the tank is empty. Be careful!!
Drills make heat and tiny sparks, gas takes very little fumes to blow up.
It has been suggested to me that the return fuel line needs to be smaller to keep the right pressure in the motor, or carburetor. That having the same INSIDE diameter fuel line for both feed and return, may bleed the gas back into the tank, and not supplying the power needed to drive the machine.
I'm not entirely sure if there is a pressure issue or not, but I have been down this road before with the fuel lines being different diameters in the past. What I did was put some boiling water in a mug to warm it up and found a nail of appropriate diameter to push it on to in order to stretch out the hose. It took several tries of pushing it on and putting it back in the water to soften up, but eventually I got the end swaged out enough. I also did the same thing on a car much more recently by heating up an old deep socket held in vice grips. If you use a nail be careful because they can be a bit jagged, so smoothing it out with a file, sandpaper, rock or whatever you have available will keep from cutting the hose open.
Hair dryer will not probably get it hot enough. Best tool is a heat gun <$10 harbor freight. then you can dilate the hose better since it will go to 1000F. I would avoid changing the diameters, because small engines are often designed to use the hose structure as a flow control in concert with the carb, especially for tools that run while in different alignments. I'm a little worried that your carb kit had a smaller gas line diameter, check the reviews where you bought it to see what people have been doing for sure.
Small engine repair sucks! I'm reading Dale's threads and dreaming of lithium tools. I use them to set the chicken net and it is just a constant battle.
Standing on the shoulders of giants. Giants with dirt under their nails