Converting to a Four Stroke

[Wayne]

I have a 1978 ODAY 23 powered by a 1979 Johnson 9.9 . I would like to change to an electric start four stroke of equivalent power ( not less than 8 HP ).Will I need to reinforce the transom and if so how? Also , will the original motor bracket need to be changed to accomodate the extra weight? If so , does anyone have any suggestions for a bracket that will adapt to the existing mounting block or is there some way to work around the block? Anyother suggestions will be appreciated. Thanks .

 

[Mike]

Not as simple as it looks

I had the same thoughts you did last year. Here's what I learned:the original mounting bracket is not strong enough to handle the torque generated by a four stroke. You need to replace the bracket. Get one that specifically states it can accomodate a four stroke engine. Rudy at D

 

[John Thomson]

I Previously Converted to a Four Stroke

You are right to be concerned about beefing up your motor mount bracket to one that can support the weight and torque of a four-stroke. I mounted a 4 stroke Yamaha 9.9, but it is somewhat overkill. An 8 hp. should be enough. Check out Garelick - your local marine store can help you out. I got their upgraded aluminum mount for a four-stroke (rated 40 hp.). It has a wider mounting base than the fiberglass/resin filled wedge that is mounted on the transom. I had a stainless steel plate fabricated to fit over the wedge and upgraded the bolts holding the wedge and mounting plate to the transom. You may want to remove the wedge and replace it with a wider wood wedge. Give it plenty of coats of resin. I also used wedges on the inside of the transom so the bolts could be at right angles (they come thru at an angle). My transom is stong enough, but check out your guncheon/pintle thru bolts and cockpit drain - had some rot (re-drilled/back filled with epoxy - upgraded to bronze thru hull fitting). Its all worth the upgrade - heard too many stories of four-strokes taking a swim because of undersized brackets and mounts. My four stroke has been great for cruising - and the weight has not slowed me down too much (have several class trophies on the mantle piece to prove it).

 

[Josh]

Check Honda's again....

You might want to take a look at the Honda's again.http://www.honda-marine.comThe weight has come down to about 105 lbs. for a 9.9 HP, and the 8hp even have electric starts. I was looking at them for awhile, and am concidering them. Cheap, light weight, reliable, many diffrent options and types. I'd have to go back and check, but I think electric trim was even available.With the weight of the Johnson you have now, you'd probably be loosing weight!As far as the brackets, that I don't know about. I'll be asking about that as soon as I get my Oday 22 in two weeks!Josh