Small Engines (Lawn Mowers, etc.): 445 john deere, john deere lawn tractor, john deere lawn

Question
what are some possible causes for vibration in the engine of my 22 horse power 445 john deere lawn tractor?

Answer
Loose motor mount bolts, loose crankshaft pulley, severe intake leak, bent push rod, incorrect valve clearance...lots of stuff could be the problem.

Does the engine run smooth and have sufficient power?  I'd check the mounting bolts as they are relatively easy to access and check.

Did the vibration start suddenly?  Any maintanance before or after the vibration started?  Did you replace the spark plugs?

Let me know.
Eric