Abstract: A wrench for gripping and turning an oil plug of a Briggs and Stratton engine, and including a working head at one end of a handle, the head having a circle of openings for receiving a pair of upward posts formed upon the oil plug; and the improved plug wrench, in one design, including a circular groove on each side of the head for guiding the posts into the openings each time that the wrench is disconnected, and then reconnected, while making several partial turns of the handle.