The correct engine for that tractor is an Onan B43M - GA016 C24787 - SPEC # 3419A and 3552A
The Spec for the Onan Performer 20 that is in the Craftsman will not be the same but here are the issues.
The crankshaft has a stub that sticks out the rear of the engine block. The diameter and length are what matter as long as the stub shaft is not tapered or splined. The shaft must be round and have a keyway cut into it for a rectangular piece of key stock.
You will need a jaw type coupler (Lovejoy) that will fit onto the crankshaft output stub and also onto the hydraulic pump input shaft.
If the pump mounting bracket is still in the tractor along with the pump, then the pump may still have one half of the Lovejoy coupler. A new Lovejoy half of the correct diameter can be purchased along with a new spider that fits in between the jaws of the coupler.
Choke and Throttle cables can likely be adapted.
One main issue will be whether or not the original mechanical PTO clutch is still there or it disappeared with the old engine. If it is gone, then you need to find a good, used EZ Adjust clutch from another Onan engine or buy a new one for about $600.00 from a dealer. You cannot cut grass or blow snow unless this clutch is in place and in good working order. It bolts directly to the engine flywheel on the front of the Onan.
You will need the four rubber pucks that go UNDER the frame plus the 4 bolts and Nylok nuts that secure the engine to the frame. Do not mount that engine without new rubber pucks or you will break off the mounting ears on the oil pan.
Connecting the fuel line is simple and matching up the wiring should not be difficult either but the big issue will be the exhaust system. The muffler and pipes used are exclusive to the Case tractor but....it is possible to create your own exhaust system if you are good with a MIG welder or better yet.. a TIG welder. If after reading this you still want to proceed with this project, then perhaps you will find it advantageous to e-mail me.
