So I repropped and.....

[itsaboattime]

I have an '87 Evinrude 110 that had a 13 1/4 X 17 prop when I bought it. I could turn over 6700 rpm at wot. I bought a new Turning Point 13 1/4 X 19 prop. I can still twist around 6000 rpm out of it. Now my outboard is supposed to turn 5200 to 5500 rpm at wot.
My question is should I stay with the new Turning Point and run a little slower, keeping in mind that I can get a lil more speed in case of emergency, or do I bump up to a 13 1/4 X 21 and see if the wot rpm comes down to 5500?

 

[Bob_VT]

Re: So I repropped and.....

Try this..... Drop the motor down one hole and see if that gets you into optimum range and control. It would be cheaper then a prop

 

[jestor68]

Re: So I repropped and.....

Have you verified the accuracy of your tachometer?

 

[itsaboattime]

Re: So I repropped and.....

Power TNT. The outboard is normally trimmed down'

Haven't verified the the Tach. I have been kicking around the idea of getting a new one. I am planning on re-doing my helm and a new tach is on the wish list. I think your on to something there Jestor, I will check that first.

 

[limitout]

Re: So I repropped and.....

I have an '87 Evinrude 110 that had a 13 1/4 X 17 prop when I bought it. I could turn over 6700 rpm at wot. I bought a new Turning Point 13 1/4 X 19 prop. I can still twist around 6000 rpm out of it. Now my outboard is supposed to turn 5200 to 5500 rpm at wot.
My question is should I stay with the new Turning Point and run a little slower, keeping in mind that I can get a lil more speed in case of emergency, or do I bump up to a 13 1/4 X 21 and see if the wot rpm comes down to 5500?

just based on the numbers you have given and if you looked into other things like trim and engine performance then yes it sounds like you need the 21* to put you right where you should be.

 

[steelespike]

Re: So I repropped and.....

what speed are you turning at 6000?

 

[itsaboattime]

Re: So I repropped and.....

Steelespike, my GPS took a swim earlier this summer. So I am not sure exactly how fast it's going.
The boat is an '82 Four Winns Marquis 160 F&S. 16 footer. When I bought the boat it had a 50hp and the speedometer only goes up to 35mph. I need to replace it with a bigger one. Another thing for when I redo the helm.
At wot the speedo will twist around and hit the back side of the "0" mph pin.

 

[steelespike]

Re: So I repropped and.....

Perhaps you could borrow or rent a shop tach to confirm your rpm.Or maybe a friend with a gps,some cells have a gps app.
Boat is about 1075 lbs dry weight,motor about 307.
At 6000,2.00 gear ratio,19" prop 12% slip, calculator says about 47.5 mph.
I think I would stick with the 19and be careful until you can confirm your speed and or the rpm.

 

[itsaboattime]

Re: So I repropped and.....

Perhaps you could borrow or rent a shop tach to confirm your rpm.Or maybe a friend with a gps,some cells have a gps app.
Boat is about 1075 lbs dry weight,motor about 307.
At 6000,2.00 gear ratio,19" prop 12% slip calculator says about 47.5 mph.
I think I would stick with the 19and be careful until you can confirm your speed and or the rpm.

Yeah, that was kinda the conclusion I came to after reading the above replies. I have some work to do.
Thanks!