Decrease the pitch and you will move slower. However, you will achieve a higher rpm when you are wide open. Possible to over rev that little beast when you are cruising.
Unlikely that you have a tach on it to tell.
I have one of these on a 14' fiberglass skiff and it is a great little rig!
US Navy has a perfect record in aviation. We have never left one up there.
26 TV Weekender 04 Suzi 115 x2
37' Lafitte 87 Cummins 6BTAM2
23' Wellcraft Coastal 93 Johnson 225
50' Chandeluer Lugger 60 Detroit 671N
65' Breaux Brothers 85 Detroit 12V71TA X2
135' Breaux Brothers 88 Caterpillar 3412 X4
25' C- Hawk 87 Johnson 225
19.6' Aquasport 87 Evinrude 140
16' Hobie Cat 74 wind