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stratus5
 In my search for the right prop I've found through trial & much error that my short shaft gearcase has a different gear ratio than the long shaft, 1.83 I think offhand.
All the recommended props for this motor are too much load.
I bought it with a 12 3/4 13, which would turn over 6000rpm on my 9' mini boat with almost zero slip.
Went to 12 1/2 15, which produced 5200rpm, and better top speed around 40. There was no in between size, so I filed off some of the cup & got the rpm to 5600, 43mph.
Went to a SS prop, and had to do the same thing. The slip calculators tell me Im around 2~3%.
I believe I need a smaller diameter, higher pitch prop, but I can't find a 17P in a smaller diameter. I have no hole shot, and can barely pull a skiier up, and I think a smaller diameter would give me more slip, letting the rpm spin up better during the holeshot, and the lower surface area & drag will be made up for with the extra pitch, at speed.
my boat is very small & light, like an addictor 245, empty hull under 400lbs. Seems Im stuck with prop diameter designed for the lower gear ratio of the larger leg motors, I haven't even seen another motor this size with a short shaft.
Im thinking of trying a 17P prop, & fileing the diameter down to get the right rpm.
Any suggestions?

Thanks, Dan

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outboardwizard

Hello depending on engine height and set up an over the hub type prop would work best for top end. if engine has trouble getting on plane and top rpm is OK I would try drilling holes in the hub area to allow exhaust relief and better hole shot

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stratus5
What is an over the hub prop? Wheere the exuast goes around the prop instead of through it? Haven't seen anything like it for this motor.
Im running the engine as high as I can without ventilating. AV plate about 1" above the bottom. After much experimenting with & without tabs & foils, Im using a foil on the motor which helps getting on plane greatly.
I tried drilling the holes, but it would ventilate excessivly just before getting on plane, so I've filled them back in for now..
Since Im spinning the prop faster than the typical 75, my gut feeling tells me I need to lose some diameter. The lack of slip tells me there's too much blade area.13" pitch overspeeds the motorto 6100+rpm, 15"  bogs it to 5200rpm & poor hole shot, until I took the file to it.
As it is now, it runs good on top of the water. I just can't believe the hole shot is so poor for such a big motor on such a small boat.
Thanks for taking the time to help.

-Dan

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