I recently purchased a Troy Bilt Pony with a 5HP Briggs and Stratton Model 135292 Type 0070 01 Code 9505092D engine that the previous owner has totally bent the throttle connections at the engine--I am sure trying to get it started from bad gas (varnish on the walls and stuff floating in the tank; will only start with gas spoon fed though the plug hole, then immediately runs rough and dies). These are probably repairable with carb kit and tank cleanout and parts if the connections are warped beyond repair.
But I would like to explore replacement engines as well. The only engine I have been able to find so far that has the two drives needed for the forward and reverse pullies to work is a Briggs 123435-PTO. Are there other options? Briggs? Honda? Tecumseh? Others? Electric start would be fine as the tiller will mostly be used by my 78 year old father in law.
I am fairly sure this is a replacement engine. The tiller appears to have had a battery at one time but this is a 1995 recoil type motor. After looking at every square inch for two days, I have not been able to date the tiller. The part number molded into the transmission is 20690 and the number on the drive shaft is too short and unreadable (?0762). Neither appears to start with a letter. Sorry for the long post but I hope this helps with more specific answers.