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Very confused and in need of expert opinion

Mikk Wardwell

New member
I bought, what I was told is, a 1988-89 Johnson 115. It needed a prop and a starter/solenoid. Being that I had a blown, yet complete, Johnson 115, I figured it’d be an easy swap/fix. Come to find out, despite having a 115hp V4 cowling, I actually purchased a 1988 Johnson 88hp. I was still able to use my starter/solenoid and the motor runs very nicely. My problem is the prop. It’s supposed to have a 13 spline shaft, yet it has a 15 spline. Will any 15 spline prop fit? And what size/pitch would you recommend for a 15’ fiberglass trihull? I mainly fish for bass, steaming from spot to spot, where I always switch over to my electric trolling motor. Occasionally I do take my kids tubing but, aside from that, I usually run wide open to wherever I’m going. Any help would be greatly appreciated. Ty!
 
Prop selection is an art not a science. You gain in one aspect of performance but lose out in another. Yes, pretty much any 15 spline prop will fit, as long as it isn't too big a diameter. Since you are not only pushing the boat but towing a load, you probably want a lower pitch prop that will give you better "gearing" at slower speed. I would also stick with a modest diameter like a 13.75 x 17. If you want to give up a little bit of towing ability, then go up to a 13.75 x 19. These may or may not hit the sweet spot of 4500 RPM at wide open, so you might find that some experimentation is needed. I wouldn't even try anything with a pitch over 19 only because it'll be difficult to get up on plane with a load esp. a tube. Avoid plastic/composite props
 
Excellent. I have a basic knowledge of props but my experience is more commercial….semi planing 30’ and bigger lobster and dive boats with inboard diesels. I was thinking of getting a 14” or 15” x 15 or 17 pitch and going from there but I know enough to listen when someone wiser than myself speaks. A 13.75 x 17 it is, then. Thank you kindly and happy boating!
 
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