Small Engines (Lawn Mowers, etc.): Lawn mower repair, crankshaft seal, pan gasket

Question
I haved a Troy-bilt 22" walk beind lawn mower - probably 8 - 10 years old with a Tecumsch Vector engine (size? I am not sure - 5 or 6 horse).  The mower runs fine, but the engine is discharging oil onto the deck of the mower - just covers the deck with oil, in about 15 minutes of mowing.  Took off the shroud, air cleaner, carb., all the external stuff on the engine, but cannot tell where the oil is coming from.  Any idea what is causing this proble.  Your response would be appreciated.  Thanks.

Answer
 Hello Paul:

 There are Several Possible Causes for this Problem. 1- The Crankcase Pan Gasket is Leaking. 2- The Lower Crankshaft Seal is Leaking. 3- The Upper Crankshaft Seal is Leaking. 4- the Crankcase Vent is Bad and Blowing Oil. Send me the Model Numbers Off of the Engine, Please. With these Numbers I can View a Breakdown of the Engine and Better Assist you. Hope this Helps. Let me know what Happens, Please. Thanks.

 Good Luck

 Respectfully

 John