Thread subject: Whaler Central - Boston Whaler Boat Information and Photos :: 1982 Montauk with 90HP ETEC Mounting

Posted by Old Blue on 07/20/17 - 10:01 AM
#1

Hello all, I have a 1982 17ft Montauk. I recently repowered it with a ETEC 90hp. I am wondering about the correct mounting height of the engine and the best prop for this boat. Right now the engine is all the way down on the top mounting hole and the prop is an aluminum Rubex 17-16. I am only getting 33-34MPH at 5000 RPMs. No gear in boat, 18 gallons of fuel , two batteries under console, and just me at 160lbs. In addition, I'm getting a significant list to port when on plane. I'm thinking about adding trim tabs but think I should address the set up first. Does anyone have an idea of the correct set up for this boat. Thank you!

Posted by Weatherly on 07/20/17 - 10:35 AM
#2

You should raise the Evinrude E-Tec 90 3 cylinder inline to "3 holes up" and invest in a stainless propeller BRP Viper 17 pitch.

Posted by Finnegan on 07/20/17 - 11:30 AM
#3

Tell us more about how the engine is bolted to the transom, as it sounds like yours may not be done properly, by definition.

Your hull has the shallower depth inside the transom, and if the engine is down all the way in the first set of holes, that would mean the bottom set of holes would be 8" lower, (9 - 7/8" below top of transom) Doesn't seem like those could be through-bolted on the inside? Lag bolts for the lower bolts should not be used. And if that is case, raising the engine up 2 more holes won't be possible without filling the lower holes and re-drilling. The Evinrude installer may have done your installation wrong.

You should be able to get 40-42 MPH out of that engine on a Montauk.

Posted by Phil T on 07/20/17 - 11:38 AM
#4

To help with Finnegan's point, read this:

http://www.whalercentral.com/articles...icle_id=82

Don't go back to the dealer that installed the engine and gave you the prop because it is clear they have absolutely NO IDEA WHAT THEY ARE DOING!

E-TEC's like to be mounted HIGH for a Boston Whaler. 3rd or 4th hole up.

See http://www.whalercentral.com/articles...cle_id=106

Regardless of what kind of water you travel, use a stainless steel prop. These suggestions are taken from Whaler owners who have this motor and done testing. Weatherly's is a good choice or

13.5 x 20” Raker
13-7/8" x 17" BRP Viper
13-1/4" x 17" SST (mounted only 2 holes up)

With a light load running solo, trimmed out you should hit 41-44 at sea level.

Change the height and prop then see if there is a tilt. If so, it is probably the trim tab on the motor that needs adjusting.

Edited by Phil T on 07/20/17 - 11:39 AM

Posted by Weatherly on 07/20/17 - 2:17 PM
#5

Technical note: There is no "4 holes up" mounting position on the E-Tec 90 3 cylinder inline; there is a 4th mounting hole as it is referred to in the Evinrude owners' manual, but this translates to mounting the motor "3 holes up."