1995 Johnson 70hp w/ 13 1/4 x 21

[bg4748]

I have purchased a 1996, 16'2" Scout. The motor came with a 13 1/4 x 21 SS 4 blade prop. Took it out for the first time yesterday. Opened it wide and got 4600 rpm's but the stern just dug in and the bow went sky high. After fideliing witht the trim, KI got the bow down and we were running ok until I backed off just a little at which point the stern dug in again and the bow went up. 3000 rpm's and we were going about 5 mph. I also have a 13 7/8 x 17- 3 Blade which i haven't tried yet.

Does this sound like a prop problem?

 

[steelespike]

Re: 1995 Johnson 70hp w/ 13 1/4 x 21

The 17 is a lot closer to what you need.It may put you about 5400.
It will be interesting to see if it will stay on plane.While the 21 is way too much prop usually a 4 blade helps stay on plane better.

 

[bg4748]

Re: 1995 Johnson 70hp w/ 13 1/4 x 21

Since I'm not at all happy with the 21, I'll either trade or sell it. What prop would you recommend for my configuration? Forgot to mention...I weigh about 300 and my passenger is about 200 and the boat is rated for well over 600.

 

[steelespike]

Re: 1995 Johnson 70hp w/ 13 1/4 x 21

So your close to max weight with 2 adults aboard.That may explain the difficulty staying on plane.I suggest a 17" Solas Amita 4 blade prop.I'm not aquainted with the more exotic props but I've seen very good results with the Solas Amita typically a predictable prop that improves hole shot,stays on plane with less power.Allows higher motor mount and trim.Also can be more responsive around the dock.Your antivent plate just above the prop should be about even to a little above the bottom of the boat..It would be interesting to see your results.