I have a 1996 Concept 21' and I believe I am experiencing vapor lock on the fuel tank. I looked at the vent line from the fuel tank and it runs side by side with the filler tube and the vent line just connects back to the fill port.... so when the gas cap is on and tightened it creates a closed loop for the vent line back to the tank. Anyone have any advice on how to vent the tank so it can actually breathe? Is this really how Chris Craft designed this? I cannot find any diagrams to show how the vapor line is supposed to be run...
Pic for attention...

This forum is for Concept brand boats. Coincidentally, I owned a 1992 Chris Craft Concept 208 but cannot answer your question.