Realize this is an old thread but hoping maybe to get some info. I have a 1210 with a broken crank S723 motor. I found a complete S753 motor. I like the idea of a little more HP but big concern is will Flywheel bolt right up and other items?I believe the engine you have is a 723 . 72MM BORE , 72MM STROKE and 3 cylinders . There are some 713 engines floating around that should bolt right in . Len Shaeffer here in the states might be able to help . He posts here often .