Small Engines (Lawn Mowers, etc.): briggs vanguard twin cyl. 14hp, code numbers, model type

Question
John, I am getting oil through my air filter, the oil drips onto my muffler.Any ideas for probable cause and possible repairs?The tractor is 15 yrs old but has been well maintained.The oil has not been overfilled.Thank you.  

Answer
 Hello Chris:

 It Could be the Crankcase Vent Isnt Working. Send me the Model, Type and Code Numbers Off of The Engine, Please. With these 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