Small Engines (Lawn Mowers, etc.): craftsman lawn@garden tractor, sears craftsman lawn tractor, craftsman lawn tractor

Question
I reciently rescued a complete sears craftsman lawn tractor mod. #ST16 from the shreder. the man said it was still being used as of spring 2011 but then quit he did not know why but said it had been taken apart and put back together and still would not run,I put a battery in shot a little gas in carb and it fired rite up.
I will not disturb the internals unless i absolutly have to, as i can see that it was put together with what apears to be gasket cement.

I have no owners man. so here is engine mod. #143640022 and ser#4070e these are off the engine shroud also says cast iron for long life with solid state ign. and equiped with timken bearings.  In my 45 years around small engines i have never come across this type as it is of the overhead valve pushrod type.

Now for the mower it self, mod# 91725743 ser.#4550. what i would like to know IS manufacturer, year,horse power rating,and where i can find owners and shop manules as well as parts because sears no longer offers them. if you need any other numbers please do not hesitate to ask.

Thank you very much for any help you can give.  DAN.

Any help or

Answer
Dan
Sorry none of the engine  numbers match 143640022 that is the tractor number not a engine number.Please look again, the numbers on the engine should read Model # xxxxx type xxxx code xxxxx The mower itself has a Tecumseh engine in it.

I think this may be your engine copy and paste this.

http://www.searspartsdirect.com/partsdirect/part-model/Craftsman-Parts/All-Produ