The Mercruiser oil drain pump attaches to the threaded fitting on the top of the dipstick and pumps oil from the engine crankcase.Fits: Mercruiser, OMC and Volvo Penta engines with a threaded fitting on the top of the dipstick tube or oil drain hose, and Mercury/ Mariner four-stroke outboards. The Mercury/ Mariner 8/9.9 four-stroke also requires a special adapter (Part Number 828369)Mercruiser Part No: 802889A1