I run a Turbo Flats IV 4-blade on my 99. Works great - good hole shot and 40 MPH @ 6000 RPM. I was told by the selling dealer that the lower unit is from Mercury and Mercury props fit!
use the site, <br /> http://www.boat-props.com/propellers/ <br />best answers - any brand. Just verify the pitch.<br />on your engine should be 13 or 15.