Whaler Central - Boston Whaler Boat Information and Photos

Posted by twin242ls on 05/13/14 - 3:45 PM

Newish to the board. After a rebuild of my 1984 evinrude 90 v4 on my 1978 Montauk I am looking to re prop.

I raised the motor from the blind holes to the highest it will go. I am running the stock original 17. It now over revs and slips too much in the mid range.

Looking for a 4 blade for cruise. any suggestions or input? we pull kids on the tubes and cruise so a high perf 3 blade is out.

(please follow guideline #1 on the front page and use the full 4 digit year)

Edited by Joe Kriz on 05/13/14 - 3:46 PM

Posted by Joe Kriz on 05/13/14 - 3:55 PM

It now over revs and slips too much in the mid range.

Please define over revs.
What is the WOT range of your motor and what are you getting now?

I am running the stock original 17

What is a stock prop?
Aluminum? SS?
What brand of prop? OMC?
And the pitch is 17 ?

A 4 blade prop may not be the best. There is nothing wrong with a 3 blade.
Nor raising your motor all the way up may not be the best for you motor/prop combination.
See this article to get you started.
http://www.whalercentral.com/articles...cle_id=108

Posted by twin242ls on 05/13/14 - 3:58 PM

it is an aluminum original 1984 17p omc prop. and by over rev I mean it is over 5k

thank you for the link, I have lots of experience propping io boats but have no experience with ob motors. looking for real world experience.

(moderator note: please follow guideline #1 on the front page and use the full 4 digit year)

Edited by twin242ls on 05/13/14 - 4:02 PM

Posted by Joe Kriz on 05/13/14 - 4:02 PM

5k is not over revving for that motor.
I believe the WOT operating range is around 5500 RPM's

Many newer motors are around 6k
Take a look at your manual and it will tell you the WOT range where the motor should run with a light load and let us know.

Posted by twin242ls on 05/13/14 - 4:12 PM

5 k max rpm turning 5600 at wot.

regardless. I am looking for a suggestion based on experience not an add. would like a more efficient modern prop that works well with this hull.

Edited by twin242ls on 05/13/14 - 4:17 PM

Posted by Joe Kriz on 05/13/14 - 4:17 PM

As I mentioned, your motor may be too high for the prop you have.

Buying a new prop is up to you as you mentioned something about a 4 bladed prop. Wouldn't you have to buy one of those or do you already own one?

Try lowering the motor one hole and see what your WOT is and that will also probably help with the slipping at cruise, etc.