Repairs MTD Shredder/Chipper/Mulcher 5HP Tecumseh - disassemble and change engine?

[donlode]

Hello,
I have a MTD Yard Machine Shredder/Chipper/Mulcher (245 643D000) with a 5HP Tecumseh engine that isnt working I want to disassemble it and change the engine, since Tecumseh spare parts are hard to find and it is very old. Anyone removed an engine from this type of shredder before?

So far I have removed the rotating hopper (ref no. 21), Flail Housing Assembly LH (ref no. 41) and the blade (ref no. 1), but how do I remove the Impeller Assy Comp (ref no.12) out? I thought if I remove the blade then it would come out? Do I need to screw it out and what is holding it to the engine shaft? I have attached the diagrams.

Thanks

 

[ILENGINE]

The impeller may be rusted to the crankshaft on the engine. The engine could be a taper shaft, or just a straight shaft. I would prefer a taper, because getting it off of a straight shaft may be fun. Start with penetrating oil and let it soak, may have to find some way of getting a puller on it, without bending the impeller.