Fuel tank cross over

Good morning,
I have a fuel tank cross over pipe with valaves on our 1989 36 marine trader. The valves are located at the bottom front of the tanks. The tanks are outboard on the port and starboard sidd and hold 150 gallons each.
I did a 40 mile run and opened the sight glass valves to gauge fuel consumption and noticec the port tank was lower. The crossover valves were opened but the tanks did not equalize.
Any thoughts on Clearing the crossover line. It is 1/2 copper
I would appreciate any input

I'm sure you can close the valves on both ends of the line and disconnect it. Take it out if you can or use compressed air in place to clean it out. (I don't want to be there when you do it)


What makes you think the cross over pipe is the problem? Mine is always open but the boat has a distinct list to one side after a run. It's caused by the fuel return line only going to that one tank. It takes overnight for it to equalize.

Cross Over Valve Issue

Try closing the valves while underway, and opening them while in port. If that doesn’t solve the problem, then do the work to clean the valves and tube.