Re: 1950 mercury kf5 impeller????? Home › Forum › Ask A Member › 1950 mercury kf5 impeller????? › Re: 1950 mercury kf5 impeller????? fastjohnUS Member - 2 YearsReplies: 147Topics: 42 March 24, 2018 at 3:15 pm #72955 OMC 386084 or Sierra 18-3050 should work if you reduce the height and make the notch for the drive pin a little bigger.