Small Engines (Lawn Mowers, etc.): mower engine sizes, blade tip, hp engine

Question
Hi
  I have a self propelled walk behind mower with a 6hp engine. The model number is 12a-529n062. I would like to know is it possible to replace the engine with one that is larger, like a 6.5-7.0hp engine.

Answer
Please get me the Model Type and CODE number off of the engine.  You gave me the model of the mower which i sincerely appreciate.

You will not notice the difference in one horse power as horsepower is rated at 3600RPM.  your mower never reaches 3600 RPM.  (ANSI STANDARDS re Blade tip speed settings)

Power is now rated in torque,  EXAMPLE  a 6.5 hp engine is now rated as an 8.0 Peak Power engine

Confusing as hell I know...

If you do change your engine make sure that the crankshaft is the same size, mounting patterns, threads in crankshaft are the same, etc...