some of you have come up with very valid points.

I forgot to mention in my first post.
i have a flair lark that was fitted with an OS61 fx until the sleeve died (famous liner flaking).
I spent hours cutting the cowl carefully so it would be as clean as possible. (OS 61 fx has a rear needle)


And as for going with a .61... i have a tuned pipe on my plane and i have been told by many members here that a .61 w/tuned pipe acts like a .72,
i do not want to rip my firewall off from overpowering the plane and even then with a .61 it is still allot of power for this plane....

Here are the engine recommendations from manual....

Engine 0.63 - 0.70 4 stroke
0.46 2 stroke



As you can see a .61 is BIG compared to a .46! but to be honest i don't see how a .46 could lift this thing off the floor.

Adam