I recently purhased a used GTX 550 fan and am concerned about the mileage. Are there any suggestions to improve fuel economy or are these engines typically hard on gas? I was running on a groomed trail and hard snow for most of the trip and wasn't to the bar. I went 90 kilometers and needed to look for a gas station to fuel up as my gauge was showing empty. I put in 30 liters and estimated that I had 10 litres left in the tank ... good thing. My fill up quickly converted to 3 kilometers to 1 litre ... seems low when compared to an older 380 Touring E that I had which seemed to go forever on a tank of gas.