Whaler Central - Boston Whaler Boat Information and Photos

Posted by GNolan on 12/03/14 - 6:42 AM

Hello Everyone

I bought a 1983 Outrage with original 150hp Johnson 2S. I am sure the motor is tired after 30+ years. I am considering replacing the 150 with a 90-110hp OMC 2S. My reason for this is economical and the supply of 90-110hp used outboards is relatively plentiful. Is this a mistake to do this? Will the 90 have adequate power for an Outrage 18? Will fuel use be significantly reduced? How much or what will be the top speed potential and/or penalty?

I once owned a 17SS with a 90hp. With a 13x19 SST, a Jack Plate, and some fine adjustments I was able to get over 50mph. It was a bit concerning going balls out in this boat because it felt like at any given time the bow would lift and blow up and over. It was a thrill though. Still have some kid in me!

Your thoughts and comments are appreciated.

Regards, Greg

Edited by Joe Kriz on 12/03/14 - 10:02 AM

Posted by Finnegan on 12/03/14 - 12:20 PM

First of all, as one who runs 20" TWIN 90's on an Outrage 18 (see personal webiste link), I think the 90 will be minimal power for the Vee hull. Figure 35 MPH max, and even for moderate speed cruising, running the engine at continuous high RPM.

But more importantly, finding a used 25" shaft OMC 90 will be almost impossible, and even finding a used 115 V-4 25" shaft will be a problem. Which means you will have to do a 5" extension kit, which installed could run around $800.

I would highly recommend a single 115 if you want a low power solution for the boat. You have a much
change of finding a later model used XL 115 than an XL 90.

Posted by GNolan on 12/03/14 - 12:34 PM

Thank you for you input. I agree with you. After reading so much data I have decided to go with a 2000 or later 115hp Merc or OMC. I plan to use a Jack Plate to tune set-up. You just confirmed my thoughts. Think I can get 40mph plus with a 600lb (including fuel) payload?

Thanks...Greg

Posted by Marko888 on 12/03/14 - 7:16 PM

If your boat has a clean bottom with no paint, you might get to 40 with a 115 2-stroke. I did a lot of reading before re-powering, and most 18's with a 115 2-stroke were getting 36-38 mph at WOT.

Of those, most who run somewhat light most of the time (or in the ocean a lot) are happy with a 115 2-stroke on an Outrage 18.

Edited by Marko888 on 12/03/14 - 7:21 PM

Posted by Finnegan on 12/03/14 - 9:25 PM

I would also be on the lookout for a 4 cylinder Mercury 125 2-stroke, manufactured though 2005. They are the same engine platform as the 115, but put out considerably more power. But also, fiinding any one of these in 25" shaft could be problem, although the after market extender kit is still an option.