Q: Six years ago I purchased a new 25 hp 4-stroke carbureted Mercury outboard motor. The carb is now suffering the effects of ethanol—a clogged fuel port stalls the engine at mid-throttle. I ...

Although it’s become a standard in the automotive industry, ethanol remains a bane for boaters running two- and four-stroke outboard motors. Traditionally, E10 (10 percent ethanol blend) was the ...