Actually if it is like some the Briggs that I work on it could be. The Briggs even with a leaking head gasket can run very well but they consume excessive oil as the blow by product is fed through the carburetor and burned. Most time they don't even smoke, just reports of excessive oil usage.
A simple leak down test could tell if it is a head gasket or worn cylinder causing the excessive crankcase pressure. When preforming a leak down on an OHV you do want the valve off so you listen to the push rob galley for leaks.
