my .61 and .51 ST all took about a gallon before they came alive. I could tell the difference for sure. My OS 1.60 FX was a finicky PITA that cost me a plane because of a deadstick. After that I ran a jug of fuel through it on the ground and that helped. Ringed motors just take a while to break in. I have a new 2300 still in the box that will get a gallon through it before it even leaves the ground.