Small Engines (Lawn Mowers, etc.): OLD RIDING MOWER, sears catalouge, timken bearings

Question
I am trying to get information on my brother's old riding mower. It's ENGINE MODEL NUMBER: HH100-115207E (serial #42201). The mower itself just says "Craftsman" and "TIMKEN BEARINGS." The mower itself is MODEL NUMBER: 91725722 (serial #10714). We did a little preventative maintenance on the mower and were very impressed with it's strength and performance. The blower housing also says it's a cast iron engine?
If you can shed some light we would appreciate it.
Especially the horse power.  

Answer
DEL, SOUNDS LIKE A OLDIE BUT A GOODIE.  WHAT I WOULD DO IS
GIVE A SEARS CATALOUGE STORE A CALL.  THEY MAY COULD FILL
IN ALL OF YOUR MISSING BLANKS WITH THE INFORMATION YOU HAVE
OR VISIT A LAWNMOWER SHOP AND SIT DOWN OVER A CUP OF COFFEE
WITH THE COUNTER HELP SOMETIMES THERE IS AN OLD FELLA IN THE BACK LIKE ME WHO CAN BE OF SOME GOOD HELP.  I THINK IT IS A 10 HORSE.  TECUMSEH.  MOST CRAFTSMEN ENGINES WERE BACK
THEN.
I HOPE I HAVE HELP A BIT.
MERRY CHRISTMAS,
GEORGE