Patent attributes
In an internal combustion engine, an oil-filler-port/oil-level-gauge attachment hole is formed on a side of the internal combustion engine. An oil-level-gauge for measuring the amount of oil in the inside of the internal combustion engine extends within the oil-filler-port. The oil-level-gauge is formed integral with a cap for the oil-filler-port. A guide cylinder portion for guiding the gauge deep inside the oil-level-gauge attachment hole is provided to extend therein. A side outflow hole where the filled oil detours around the guide cylinder portion and directly flows down to the inside is formed on the way of the guide cylinder portion. A guide wall for preventing the gauge from entering the side outflow hole is formed on a lower portion of the side outflow hole.