what woulkd be good prop pitch for 70 hp on lowe fm 165 sea nymph

[horse62049]

I have lowe fm 165 sea nymph with 70 hp motor 17 pitch prop tachs at 3200 at 40 mph want to bring rpm up for pulling kids on tube not a lot of hole shot now what would be good pitch prop was thinking 14 would this be about right thanks for any help

 

[Sea Rider]

What's the make of that engine and its wot factory stated rpm ? Wot rpm will probably be still low with a 14 prop if you take into consideration 150-200 rpm per pitch decease. If so wot rpm should be increase to 3800-4000 rpm.

Happy Boating

 

[steelespike]

I'm pretty sure your tach and/or speedometer are not correct.You need your speed by gps.
What is the diameter and pitch of the prop.
I believe the tach is the culprit if it was accurate at 3200 you can't solve it with a prop change.
you need to gain 2300 rpm to get to 5500. Thats more than a 10" pitch change. Can't be done.
If you were going 40 your actual rpm would be about 6000.
I think your speed us suspect as well.

 

[steelespike]

By the way when all is said and done your 17" pitch is probably right.