Having some trouble with the fuel line for my Onan generator on my motorhome. The original metal line (copper?) that came from the fuel pump to a fuel filter to the carburetor was twisted and leaking so I decided to replace it. Onan recommended taking out the fuel filter attached to the carb as there is already a fuel filter online before the pump.
I put a 1/4” plug with a push on end into the carb. That worked great. I tried putting the same 1/4” plug with a push on end into the fuel pump. It tightens just enough by hand but once I put the wrench on it, it just spins loose and won’t tighten.
What kind of fitting should I be using? I attached some pics of what was in originally there, what the fuel pump looks like and what I bought.