In the mid to late 90's Briggs and Stratton had an issue with head gaskets in their single cylinder 14hp overhead valve engines. The problem was that the gasket blew between the cylinder and the overhead valve chamber. When this happened it instantly became an oil fogging machine. No mosquito or lung was safe. The warranty process paid for many repairs and many policy adjustments were allowed when the machine was out of warranty.
I disagree about leak down tests. Kohler and Briggs STRONGLY recommended leak down tests to check the integrity of the valves, cylinder and rings. Many small engines have a variation of an automatic compression release. This is done, for instance, by an Automatic Compression Release or ACR in Kohler "K" series during cranking. Others used a method of bumping the exhaust valve to release some compression. The latter method is not used any more due to enviromental concerns (Tier 1 or Tier2). The intake valve is now bumped during cranking. But that is another discussion. Leak down tests give a good overall picture of the integrity of the engine.
