The YS 110 is the best bet for this plane if you have the money. It has ridiculous power, its very light for the power it puts out and its the best running engine money can buy in its class. Plus it has an internal built in pressure regulator so you can put the tank back on the CG if you like. I have has OS 91's Saitos 1.20s and YS 110 and 140 engines and the YS engines are light years ahead of the others, period. They are the easiest to tune and start and the most reliable engines if you take care of them which is nothing but an occasional valve adjustment which is simple. And if you do have a problem YS service via central hobbies is 2nd to none and parts though not cheap are easy to come by.

Mike