
Posts: 3504
Location: Elk River, Minnesota | Hiya,
If you were not even getting 5100, you might find a 17 pitch to be a bit on the low side as well. The 13 x 18 steel will probably give you about the same numbers as your 13 x 19, but could be potentially less since it is a steel prop rather than an aluminum.
Roughly you can count on every inch in pitch of prop will equate to around 175 - 200 RPMs, so going to a 17 would get you to about 5500, a 15 would get you close to 6000 which would be the ideal situation.
Depending on how much you want to spend, you could try a 15 or a 17 pitch ballistic propeller on there which is designed to give excellent bow lift and great handling. you might even be able to move the motor up a hole or two on the transom to get even more RPMs without too much loss of handling.
My 165 Navigator has a 90 hp yamaha 2 stroke that has had a couple of aftermarket items placed on it to get higher top end. I am running a 17 pitch ballistic propeller on mine, getting 5400 RPM on a low humidity comfortable temp day. When it gets hot and muggy, it bogs down and only pulls about 5300, but that is due to conditions, yet is still in the upper 1/3 of the RPM range which is ideal.
Steve
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