After purging air from lines. Noticed a diesel leek from

[mbulriss]

Welcome. As an aside, it would be nice to know the year and model of coach, or alternatively which gen set engine (Perkins, Kubota, etc). Be that as it may, if you snugged down all the fuel line nuts and it’s still leaking, here’s my guess. The following relates to the Perkins Diesel engine. The fuel lines going through those nuts are flared at the ends. After years of rattling around those flared ends can develop small cracks, nearly invisible. My Perkins in my 83 PT40 did that. A good diesel parts house should have small beveled washers that you can insert under the flared tubing end and then tighten up. They look like tiny funnels without the spout. I have no idea what they are called. Generally considered a temporary fix, mine never leaked again. That’s where I’d start looking on the leaky one. Good luck.