I had a older Sato 90 twin. This version had duel carbs ..... 2 needle valves. From what I have been told the 100 is the same engine with a single carb. They put put the same power. This is a nice engine. I have had no problems with mine. I mounted mine on a 60 size Big Stik and it pulled it around well. As far as putting it in the Stearman goes I think it is a bad idea. Here is why.


I put a magnum 91 4c in my Stearman. It was the only spare engine I had at the time. On the maiden flight the plane got off the ground in a surprisingly short run. It flew for about 20 feet and as soon as was high enough to overcome ground effect the plane tip stalled and cart wheeled down the rest of the runway. The only thing that broke was the landing gear. That was all luck. It could have been a total loss.

The plane will probably weigh about 12 / 13 lbs complete. It's heavy!
A single 91 is a lot lighter than a twin.
I have a feeling that a single will put out more power / torque. I think it cycles faster than a twin.

I'd hate to hear that you lost a Stearman because it was under powered. I would not use less than a 120.

Best of luck