Impact 1675 2017 Mercury Fourstroke 90 HP

Last August, I bought an Impact 1675 2017 with a Mercury 90 HP four stroke. I am trying to find the best props for my set up.
The boat came with a Beaksan (chinese prop…) 4 blades 13 3/8 x 15 prop. With this prop, I had a max speed of 38 MPH @ 5675 RPM.(WOT)
Change the prop for a Nemesis 4 blades 13 x 17 I had from a previous boat. With the Nemesis got 40 MPH @ 5350 RPM (WOT). The boat handle a lot better and fuel economy was great (7.8 MPG vs 7.2 with the Beaksan).

Also test with a Black Max 3 blades 16 pitch. Max speed was 40 MPH @ 5800 RPM. Fuel economy was not as good as with the Nemesis and boat handling was not too good, Have slip when trimming up.

I am pretty satisfied with the Nemesis but I know the WOT is low.

I am curious to know for those of you having a similar set up (Impact 1675 and 90 HP fourstroke) which prop and what kind of performance you are getting.

Hope my english is not too bad…

Thanks for your feedback.

I don’t run that type of boat, but I have a buddy who does. His boat performs almost identically to yours. It’s a high 30’s to 40mph hull with a fairly light load. If you’re content with how well it gets on plane and handles, there’s nothing I’d change. You could throw a lot of time, money, and props at it to maybe get 41-42mph in ideal conditions (likely at the expense of holeshot).

Here is a link to my results for a prop change.
Note: it is the earlier version of this motor with lower displacement and larger alternator output.

1675 Impact Prop selection

why is this link not working for me??

but if you search for
ido impact prop

1675 Impact Prop selection

An old bull and a young bull were standing on top of a hill. The old bull said to the young bull see all those cows down there, someday they will all be yours. The young bull got all excited and said lets run down and get one. The old bull looked at him and said lets walk down and get them all.

Top speed isn’t everything. Sounds like you have a great setup.

I run a 90 ..4 stroke on a 1750, 2017 motor and played a lot trying to get it to optimum, over 1k in props. I ended up with a 4 blade SS Spitfire X7 in a 17 pitch with best results. My motor turns it at 5500 rpms and with a full load and 2 fat guys at full trim runs 42 mph on gps. Has such a great hole shot and mid range I stopped right there.

http://www.in-depthoutdoors.com/community/forums/topic/1675-impact-prop-selection/