Mike inspect your fuel tubing carefully for a hole or tear, it sounds like you have a air leak, more times than not its in the fuel tubing. You can also check the O-ring on your fuel tank lid, if the fuel tank lid isnt closed all the way or the O-ring looks dry and brittle you need to replace it. As far as cutting the fuel tubing shorter, thats fine, they run them long for racing, racers want every last drop of fuel they can get, so by running longer fuel tubing gives them a little bit longer run time.
A bad day racing is still better than none at all.
TAMIYA TRF Racing Factory
CWRCB-Central Washington R/C Boat Club, RCUnlimiteds