Small Engines (Lawn Mowers, etc.): Oil leak from B&S engine model 46171 on MTD mower, mtd yard machine, mtd mower

Question
Hi Eric,

This is a 1998 or 99, Briggs & Stratton, 20-hp engine, Model 461707, on an MTD Yard Machine riding mower, with a 46" cutting deck.
After mowing for about 1 hour the engine got progressively louder so I shut it off. I discovered massive quantities of oil on the cutting deck and the rest of the areas under the engine. I checked the oil and the dip stick was dry.
Most of the oil seems to be on the left side of the engine (when sitting on the mower), and no apparent leaks around the drain plugs or where you add the oil.
Do these small engines have a head-gasket like car engines, and could this be the case? I've never done a job like that, but consider myself mechanically inclined so I don't mind getting my hands dirty. What do you think the problem might be and how difficult might it be to fix?

Please help.  Thank you.

Matt


Answer
There should be an inspection plate on the engine. It is a large metal cover usually on the back of the engine.  Remove the cover and check for internal engine damage.

I've seen these engines lower engine seals leak oil.  You will have to remove the bottom engine stack pulley to really get a good look at the lower oil seal.

Let me know what you find.
Eric