I see no issue with copper line or even stainless steel gas line. You may have some priming issues initially when you prime the fuel bulb. But other then that, it should work for years to come. I would personally rather have good solid copper or stainless steel fuel line runs, then mere 3/8" rubber fuel line. But that is just me. However, I would also grommet every place that fuel line goes through anything, be it metal or wood to protect it from rubbing. JMHO!