Is it possible to hook up the fuel tank selector valve backwards?

[BlueBreadTruck]

I installed a new 19g front tank today, and after filling it up half way, driving home it seemed to work for a while, then after a few miles ran out of fuel. Before the tank change the selector valve worked fine! I had disconnected the fuel lines at the valve to drop the tank, and I am wondering if its possible to hook them up backwards, or are they a seperate size? Its snowing now, but I have to check that, possible clogged vent line, and actual operation of selector.......runs fine on the rear tank. Anyone have a similar issue?

thanks for any ideas!

 

[icanfixall]

No posible way to mix up the supply and return lines.... The supply is 3/8 and the return is 5/16..... Did you look at the sender suction line in the tank... Usually the bottom shower head is broken off and we run out of fuel with 1/4 tank left. Add about 3 inches of fuel rated hose and problem is fixed...

 

[BlueBreadTruck]

Thanks, when I had the sender/pickup assy out it was fine, and in good condition.....Ok, I guess I have another problem somewhere then....