Bill Miller, Sabb America in Florida is the only dealer in the U.S. now. 888-301-1706
Sabb stopped producing the engine in 2002 after 46 years of producing the G engine. The valve guides are probably specific to Sabb. Bill Miller stocks both the shop and owners manual. The owners manual is almost a shop manual.
Parts are readily available throughout the world.
When your prop is fully feathered, is there still some pitch left in the prop???