I have a float type carb and have recently bought a carb kit. Does any body have a diagram showing how to replace the "o" rings and valve seat etc.

1. You will have more parts than you need in the kit.
2. Since Tecumseh closed shop some breakdown info has been hard to find. Check and see if there is a reference in Crigby's sticky. Otherwise try Parts & Accessories | Shop & Find Lawn & Garden, Appliance Parts at Sears PartsDirect | SearsPartsDirect.com.

Generally is a disassembe and re-assemble. I've never replaced a needle valve seat, just the fuel cut out seat which likely screws out.

It's nice to lube the o rings with silicon grease in the plumbing store.

Hi,
Some manuals here. There is another site, I just found this first. Tecumseh, Kohler, Honda, Kawasaki, and a few others available online. Briggs, John Deere and some others guard their copyrights strongly.
Tecumseh Small Engine Specifications
Peace,
Clarke