I have a 1972 13-footer that needs a "newer" engine. I have been looking for a Yamaha 30-HP two-stroke-power-cycle engine. Almost every engine offered out there is a 20-inch-shaft model. My 13-footer needs a 15-inch-shaft engine.
[How can a 20-inch-shaft] engine [be fitted on a] 13-footer [that needs a 15-inch-shaft engine]?
Fitting 20-inch-shaft Engine to older 13-footer
Re: Fitting 20-inch-shaft Engine to older 13-footer
The subject of older 13-footers needing a 15-inch-shaft engine has been discussed countless times.
If you do not select a short shaft (15-inch) then a long shaft (20-inch) will require you either install a bracket or install an insert to fill in the notch.
There are several options, including:
Transom Riser
https://www.nausetmarine.com/shop/boston-whaler-transom-riser/
https://www.kentfabrications.com/transdaptors
Engine Bracket
https://thmarinesupplies.com/collections/boat-performance/products/hi-jacker-fixed-jack-plate-4-inch
Setback Bracket
https://thmarinesupplies.com/collections/boat-performance/products/mini-jacker-jack-plate
If you do not select a short shaft (15-inch) then a long shaft (20-inch) will require you either install a bracket or install an insert to fill in the notch.
There are several options, including:
Transom Riser
https://www.nausetmarine.com/shop/boston-whaler-transom-riser/
https://www.kentfabrications.com/transdaptors
Engine Bracket
https://thmarinesupplies.com/collections/boat-performance/products/hi-jacker-fixed-jack-plate-4-inch
Setback Bracket
https://thmarinesupplies.com/collections/boat-performance/products/mini-jacker-jack-plate
1992 Outrage 17
2019 E-TEC 90
2018 LoadRite 18280096VT
Member since 2003
2019 E-TEC 90
2018 LoadRite 18280096VT
Member since 2003
Re: Fitting 20-inch-shaft Engine to older 13-footer
A c.1972 13-footer with a notched transom designed for a 15-inch-shaft outboard must be one of the last ones made with that configuration. As noted, there are not many modern outboard engines at the 30-HP power level available with a 15-inch-shaft.
In addition to the mechanical bolt-on devices that Phil mentions, another option is to re-work the transom to a 20-inch-height and eliminate the notch. An earlier discussion in this same forum demonstrates a very nice modification to a 13-footer to raise the transom. See
20 inch shaft on a Classic 13
http://continuouswave.com/forum/viewtopic.php?f=6&t=64
Also, for an example of a mechanical solution, read
Cetacea Page 56
http://continuouswave.com/whaler/cetacea/cetaceaPage56.html
In addition to the mechanical bolt-on devices that Phil mentions, another option is to re-work the transom to a 20-inch-height and eliminate the notch. An earlier discussion in this same forum demonstrates a very nice modification to a 13-footer to raise the transom. See
20 inch shaft on a Classic 13
http://continuouswave.com/forum/viewtopic.php?f=6&t=64
Also, for an example of a mechanical solution, read
Cetacea Page 56
http://continuouswave.com/whaler/cetacea/cetaceaPage56.html
Re: Fitting 20-inch-shaft Engine to older 13-footer
If you do not wish to rework the transom in some manner, I believe that Tohatsu makes a few engines with 15-inch-shaft length.
The Tohatsu model MFS25 is a tiller-steered four-stroke-power-cycle engine available in a 15-inch-shaft length. That engine would solve your problem. See
https://www.tohatsu.com/outboards/25_4st.html
The Tohatsu model MFS25 is a tiller-steered four-stroke-power-cycle engine available in a 15-inch-shaft length. That engine would solve your problem. See
https://www.tohatsu.com/outboards/25_4st.html
Re: Fitting 20-inch-shaft Engine to older 13-footer
I believe you can not get PTnT with a 15" shaft. Many people put 20inch engines on their older hulls, as Phil and Jim mention. Many people want and desire an electric start engine with power trim and tilt engine, and it will benefit in resale. And, as you know, will be much easier to find used or new.
Last edited by biggiefl on Mon Oct 07, 2019 12:51 pm, edited 1 time in total.
On my 24th Whaler. Currently in the stable: 86 18' Outrage, 81 13' Sport(original owner), 87 11' Sport, 69 Squall(for sale cheap).
Re: Fitting 20-inch-shaft Engine to older 13-footer
NICK--I think a pull-start engine on a 13-footer, particularly with tiller steering, is a good fit. Having to manually start an outboard engine gives the owner an incentive to keep the engine in proper tune and use good fuel and oil.
Re: Fitting 20-inch-shaft Engine to older 13-footer
With a tiller I totally agree. When you have to stand up, turn around, climb over the seat, battery & gas tanks to pull start the engine is not convenient, especially if you waterski.
On my 24th Whaler. Currently in the stable: 86 18' Outrage, 81 13' Sport(original owner), 87 11' Sport, 69 Squall(for sale cheap).