Small Engines (Lawn Mowers, etc.): 139ccyardman motor

Question
i replaced lower case gasket and seal now motor runs at very high rpm like governor is wide open2

Answer
What brand of engine do you have?  What is the engine model, type and code number?  Does the engine have a mechanical governor?

Have you read the information at the address below?

http://www.briggsandstratton.com/eu/en/support/faqs/adjusting-the-governor

Let me know the engine model information so I can look up what you have.
Eric