I have to Speed 13 engines. I have one in a Dirty Birdy, that the one I can't get to settle down. It runs rich then tries to lean out and if I point the nose up she really tries to lean out. I have changed the tank, the fuel lines and still have the issue. The DB fuselage only allows you to put the tank kind of high so it really gravity feeds. So I'll keep playing with it till I get it figured out.