Tecumseh Ohh50 Manual
As to my knowledge, there are no 'rebuild kits' for the entire engine, of any brand. You can purchase Honda gasket kits, you can purchase all Briggs gaskets separate, you can purchase most Tecumseh gaskets separate (aftermarket). If your engine has been sitting with water in it for years, see how bad your carb, valves, etc look.
Scribd is the world's largest social reading and publishing site.
Ohh50 Tecumseh Service Manual
Frankly it may not be worth your time to do this as it may not work period. If you just want to purchase all of the parts in the engine brand new PM me, you can purchase new carbs, heads (complete with valves), whatever you want, but seriously, thats not rebuilding, thats replacing, and at that rate just buy a new engine. Weather is not your friend on most occasions. Just out of curiosity, what do you personally think should be in a rebuild kit?., I bet I can assemble said kit and give you a price if its reasonable.:p.