Ok I have read though this post and have realized that I have done several modifications to the Haban blower and tractor though the years that I never got to mention.
I will start off with the Sears tractor first, It has a Subaru EX40 14hp repower. Reason for this is I wanted something a bit more modern but refuse to buy Chinese knock off engines. I wanted something with quality so was only considering a Yamaha, Honda, or Subaru engine. Subaru had that 1 extra hp and a better charging system so I went with that. Along with the engine swap Increased the size of the attachment drive pully by 1/2 inch but lowered the engine RPM's to 3400 max instead of 3600.
Second was the Haban blower. Haban's come with an odd chain and sprocket that cannot be purchased any longer in other words NLA. So I had to come up with a solution. The original chain size is a #41 and finding the right size chain and sprockets in this size is impossible, so I decided to swap both sprockets and chain to a more common size of a #40 often used in go-carts and is a little stronger then the original #41. At that point I found one for the auger that was just 1 tooth larger then the original, so made the gearing lower. The original is a 35T #41 and all I could find is a 36T #40. So my increase was decreased and I upped the rpms to 3500.
Sprockets available at tractor supply all I had to do was drill bolt holes.
At this point while doing the drive sprocket since it has to be welded on I put new bearings in.
So the past 3 years have been completely trouble free , I have not even worn though the original belt I put on. If not for attachment swapping and oil changes I would say I have done zero work to the tractor.
Don't even bother to bring her close to the garage anymore I am spoiled to know that she will start even in the bitter negative degree temps.
I have had newer, I have had prettier, but this is the best damn garden tractor I have ever owned.