Mon Jan 25, 2016 10:54 pm
Your one wing tank emptying faster then the other is real common in many aircraft, BUT IT HAS NOTHING TO DO WITH YOUR ENGINE PROBLEM! Assuming the plane was originally setup correctly that is, with proper sized fuel lines (1/4" ID is plenty for the Rotax) on EACH tank. There is also no way you are going to run out of fuel, until both tanks are exhausted. One tank emptying first is a non issue.
My S-7S is typical in that the right tank will empty before the left, I don't care or notice, and I sure can't feel it in the stick. Chasing the level of the two tanks around by constantly switching tanks is not needed with your plane, and has been the result of many fuel starvation accidents. It's needless busy work. Look at it this way. Your on the ground, engine stopped. You disconnect the main fuel line at the firewall, fuel will continue to run out until BOTH tanks are empty, one tank going empty sooner will not cause the other tank that still has fuel to somehow not drain. It's really no more complicated then that.
Go by the recommendations of the builders of the plane, ignore CamTom12 (sorry Tom, but have you ever just turned both tanks on and flown until the one is empty, try it, it won't quit!), and all the others that will chime in saying how you have to juggle the tanks, it's not required. Some will try and "fix the problem", thinking it's an obstruction in the vent lines or whatever, the most generally accepted reasoning is it's the different airflow on the wings caused by the rotating prop blast, or maybe it's the Coriolis Effect, doesn't matter because it's not a problem. FWIW, I've been flying for the last 20 years with no wing tank valves, both tanks always ON just a main shutoff . The only reason I stress this so much is that you must have had some other issue, it shouldn't have been the tank unbalance issue IF the plane was set up correctly to start with.
I'm leaving aside the whole argument that some do it for possible fuel contamination in one tank, but they somehow have good fuel in the other, or the ones that take off on AV gas but cruise on Mo gas, for your plane and mine, keep it simple and both tanks ON, and just use the one tank that empties last as the one you pay attention to.