This two horse had a blown head gasket and the escaping fire burned a groove into the head and the top of the cylinder. A piece of aluminum casting was also missing from the cylinder in the same area so it took a bit of machining to get both surfaces into acceptable condition again.
Another problem with these motors is the crankshaft seals. Dealer says you have to buy the lower case half with the bearing and seal already installed as a unit. Not so. The bearing and seal can be pressed out and replaced as needed. No matter what anyone says, leaking crank seals do not contribute to the cylinders low pressure. That is governed by the condition of the cylinder itself and the piston and rings.
