The
main cause of an engine dying half way through the flight
is usually a pin hole in the fuel line inside the tank.
The
tear resistance of silicon tubing is very low and it's not
uncommon to develop a hole where the fuel line is assembled
over the edges of brass tubing. If the engine runs well
on the first half of tank and then quits, it's almost always
caused by a hole in the pick up line inside the tank.