I can see the fuel line where it attaches to the carb. The engine is in a sig midstar. I will check all the lines like you said. BUT, I mis spoke earlier. The TOP of the tank is exactly level with the spray bar. I said earlier that the CENTERLINE of the tank is level with the spraybar. So therefore when the tank is full, the fuel flows to the engine easily, but when the level drops, then the fuel has to travel uphill to get to the carb and maybe therefore leaning out the fuel mixture? Maybe that's the problem?
Anyway, I will check all the lines for holes etc. like you said.
Thanks!