clunk line to carb., vent line out of tank with one wrap around tank and exit out of bottom of fuse. The fill line (3rd.) line is opposite of the vent line in that it is brass tubing that immediately curves downward inside the tank to just of the bottom of the tank floor. It can't interfere with the tank line this way and simply tip plane forward onto nose cowl to completely empty the tank. All lines are not blocked in the least amount and when pressure tested, hold for as long as one wants. This craft with this configuration has flown many hours before starting to act this way. I'm going to go out immediately to the shop and work on some projects. I will recheck everything I have stated here and rerun the engine till it either acts up or flys right. Sorry, I couldn't resist. I'll check back in this evening and if there is any change, I'll let everyone know. I really appreciate everyones help with this. Todd