Whaler Central - Boston Whaler Boat Information and Photos

Posted by redz350 on 05/13/14 - 12:03 PM

I have a 1998 Mercury 90 hp 2 stoke motor mounted on a 1998 Montauk 17'. The motor is currently mounted all the way down. What should be the best mounting height for this boat and motor combination? I seem to have seen recommencations of 2 or 3 holes up, instead of all the way down. The motor currently is swinging a Quiksilver 12.75"X21" aluminum prop. Currently the boat runs up to about 5,300 RPMs, with just one person aboard. Since I belive this boat was originally sold as a boat an motor package by a Boston Whaler dealer, why would the dealer mount the motor all the way down, if that is not the optimum position? You would think they would know better. Just wondering... Thank you for any help that can be provided!

Peter

Posted by Joe Kriz on 05/13/14 - 12:16 PM

It can depend on the prop.

However, I would mount it 2 holes up to start.
It that isn't enough, then mount it up further as needed.
http://www.whalercentral.com/articles...cle_id=106

Posted by Finnegan on 05/13/14 - 12:35 PM

The mid-range Mercurys, 75-125HP have a "taller" than normal mid-section, that is the distance from the underside of the transom bracket hook to the anti-ventilation plate is a greater dimension than most other outboards. Why they did that I do not know, but Mercury themselves say these engines should accordingly be mounted higher. When I installed a pair of these on my Outrage 18, replacing the previous Merc in-line 6's, I confirmed they needed to be run about an inch higher than the older Mercs.

I think Joe's suggestion of 2 holes up (mount engine in middle set of the five hole pattern) is a good starting point. At this height, the 21" Black Max aluminum should still give good performance, but for max all around performance, a 20" Laser II would be ideal. With the Laser you may be able to go up one more bolt hole.