Small Engines (Lawn Mowers, etc.): OIL LEAK FROM BLOWN HEAD GASKET, blown head gasket, gasket leaks

Question
I have a 6 year old Craftsman lawn tractor with a 25 hp Briggs & Stratten engine. Last summer it started blowing oil out of the block. The gasket that seals the upper and lower halves of the engine block failed or was blown out. I had it repaired , the mechanic said he replaced the failed seal with a higher quality one and I shouldn't have that problem again. He is a well known local mechanic and seems to have a good reputation. I was happy with his service and price, well at least I was happy with the results,for a while.  The mower ran fine the rest of the summer. This spring it started and ran great, the second day of mowing it began to smoke (oil on the muffler) and in a short time was blowing oil out just like last summer from the same area of the block !  Question.. what would cause this to happen and can it be properly fixed ? What would cause the pressure needed to do this? I hate to pay to have it repaired again if this will occur again.  

Answer
First off I'll let you in on a trade secret. "higher quality seal" means aftermarket part not original equipment. This engine is notoriuosly known for sump gasket leaks. It needs "original equipment" parts, not higher quality. Did he charge you for new bolts. According to Briggs they need to be replaced every time and secured with Loctite.
But this is not where yopur head gasket is. That is a completely different gasket then the one you described.
This engine isn't great to begin with, You bought it because it had a lot of horsepower. That's a sales tool. 10 years ago this tractor would of had an 11HP engine and would of done fine. Unfortunatley you paid for unneed HP instead of engine quality.
Take it to a listed Briggs dealer. Hopefully one with an MST rated tech.