im the same i like to try to figure it out myself. and when i cant and i do ask for help it always ends up being so simple that it should have been the first thing i thought of. i dont think it would be that your tank is too low from what you say. have you had the tank out? if you have a 3 line tank as you know you should have your fill line so you can get the gas in/out the line that goes to the clunk and your vent line that goes to the muffler. make sure that the vent is pointing to the top of the tank inside if it is pointing down your tank might not pressurize properly i may be way wrong and if i am i expect to be corrected