This may be an old problem that has been answered in the past but here it may be again. I had a Merc 115 four stroke with a S.S.13x17 four blade that worked pretty darn good. Hole shot was fair and top end was about 45mph. Recently repowered with a Suzuki 140 hp and have been through 4 propellers and poor performance. It came with an Aluminum 14x17 three blade and it had terrible control and top speed of about 32 mph. Put my old 13x17 four blade and it was similar to the factory. Bought a S.S. 13x21 four blade and it was better in the top end 36mph but still poor control. Went to a S.S.14x22 four blade and very good control at low speed and reverse but poor top end and a terrible hole shot with the max rpm of 5500 at WOT
I have come to the conclusion that the low gearing 2.59 combined with a 4.25'' gear case is a terrible combination. The math I come up with said I need a 20'' pitch to obtain the same top end as the old Merc and my control and hole shot experience tells me that a 3.50 or 3.75'' diameter four blade S.S. prop with moderate cupping would probably produce the best performance. Could someone chime in on this with some advise and point me in the right direction as to what I can do better and where I can find a SS four blade propeller of this size or whatever size you may suggest that will fit a Suzuki with a 4.25 gear case and 15 spline shaft? Quite a few options for the 4.75'' gearcase.
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