Small Engines (Lawn Mowers, etc.): Simpson Sears 20 Hp riding lawn mower, briggs stratton, s sears

Question
I have acquired a Simpson Sears riding lawn mower. The only decal on outside of body is "20T" and I am guessing it may be 20Hp. The body plate states Model # 917 603200, Serial # B01175. The engine is an ONAN 2 cylinder horizontal opposed 4 cycle gas with plate info of Model # B480 GA019 9/3713B, Serial # 1793489340. I have given the machine a general cleaning and it appears to run well (after installation of new oil, oil filter, air filter and one spark plug wire. This is a substantial machine - heavy frame, mower deck, etc. much like an old Wheel Horse I had - and I believe I'll keep this machine and would like to get more detailed maintenance/repair info and spec's (ie carb setting(s), ignition timing). Can you suggest where/how I can get more info on this machine like operators and/or repair manual(s)? Sears and ONAN web pages are of no use.


Answer
Hi Bruce,

Well .... I would say that if the ONAN people are not assisting you, then you might be Out of Luck.  The only thing I would try would be to

look through a Briggs & Stratton or Tecumseh shop manual and see if any of the specifications match the spec's on your machine.  Sometimes the general engine spec's are similar.

I really can't suggest anything other than that.  Sorry Bruce.

Howard