Thread subject: Whaler Central - Boston Whaler Boat Information and Photos :: 1996 15' Dauntless Repower
Posted by RobertJ on 03/19/13 - 1:49 AM
#1
Looking into repowering my 15' Dauntless with the Yamaha F70. Anyone here have a 15' Dauntless or Sport 15 with this engine that could share a picture or two?
The current engine is a 1996 70 HP Evinrude spinning a 13-3/8" x 17" OMC SST at 5900 RPM with an average load. I've done a bit of research and from what I gather the new F70 will likely not be able to turn a Yamaha 13 1/4 X 17 to at or near the recommended WOT operating range, or so I gathered.
Which prop will end up getting me in the RPM sweet spot? I already understand that I'd like to first obtain optimal mounting height on the motor. It seems many dealers are prone to mounting engines too low, I suppose to err on the side of caution with respect to water intake,but I plan on being around during this process as well as mark a reference point on the transom as to where my current Evinrude's anti-ventilation plate is in relation to the boat pad when trimmed level.Thanks for any and all input on this topic.
Oh, I almost forgot to ask...will my current transom bracket holes line up with the newer F70 bracket pattern?
Edited by Tom W Clark on 03/19/13 - 7:31 AM
Posted by Tom W Clark on 03/19/13 - 7:39 AM
#2
The holes in your transom may, or may not, line up depending on if the auxiliary ("blind") holes were used for the lower bolts on your Evinrude. If you can see all four bolts coming through the motor bracket on the outside, then you be fine. If you can only see the two upper bolts coming through, then the "blind" hole locations were used and these holes will need to be filled in the transom.
The Dauntless 15 does not have the shallow splashwell of the classic 15s and 17s so it should not be a problem.
You could probably use the 13-1/4" x 17" Yamaha aluminum propeller or the 13-1/4" x 16" Yamaha Performance Series 3-Blade, but a better prop to try might be the 13-1/2" x 16" (or *maybe* 13" x 17") Yamaha Painted Stainless Steel, or the 14" x 15" Stiletto Star 4.25.
Posted by RobertJ on 03/19/13 - 8:47 AM
#3
I appreciate your feedback Tom and I hope you are correct and the F70 will indeed spin a 17" or the 16" if mounted properly to attain optimal height. I can indeed see the bolts on the upper and lower holes of the tansom bracket of the Evinrude so I assume the current holes will be suitable.
I still look forward to viewing any images one might have showing one of these expensive little jewels married to a 15 ft Boston Whaler. My google attempts came up empty.
Posted by Tom W Clark on 03/19/13 - 8:53 AM
#5
Be sure to have your dealer mount the F70 as high as it can go on the transom, Three Holes Up.
o
o
o
o <-- Bolts through this hole in motor mounting bracket ("Three Holes Up")
Posted by RobertJ on 03/19/13 - 9:03 AM
#6
I saw three that were on the sport 15 model. Thanks for the link. Wish one of these would have refered to what prop they were turning. My first Whaler was a 15 ft sport 1983 model with a 70 Johnson and it turned a 13 X19 OMC SST to 6000 . It would serve as good comparitive info if I knew which any of these were spinning with an average load.
Edited by Joe Kriz on 03/19/13 - 10:47 AM
Posted by RobertJ on 03/19/13 - 9:07 AM
#7
Tom W Clark wrote:
Be sure to have your dealer mount the F70 as high as it can go on the transom, Three Holes Up.
o
o
o
o <-- Bolts through this hole in motor mounting bracket ("Three Holes Up")
Roger that. I had to move the present motor after I bought the rig new on this Dauntless to it's highest position. It was originally equipped with a 15" pitch and after the raise it spun a 17" sweetly.I appreciate all of your feedback on this matter.