TOPIC: 1963 OMC Dual Deluxe 17 Restoration/Re-power

Our next project will be to restore an OMC Dual Deluxe 17. We've removed and discarded the original V4 two-stroke engines which were troublesome, thirsty, underpowered and impossible to get parts for. We'll replace them with twin OMC 120 inline 4-cylinder 4-strokers using period stringer outdrives. It's going to take a little engineering but I believe I have it all figured out. I'll post photos as the project continues. Here are a few photos taken on Friday when we did our exploratory surgery. We found quite a bit of cancer but believe that a radical "floorectomy" will allow the patient to recover:

Wish you good luck on that setup. You are going to need it. Skip.

Nah!...it all has to do with weight support and distribution, floatation and "highly technical" thinking outside the box. I've done the calculations and determined that all I'll need is one fat chick sitting on the bow for counter-balance and we'll be good to go. This is the type of project that makes my job so interesting.

Actually, we decided to go with two 120's simply because there's not enough room to stuff in two big block Chevys. Then again, maybe one in the bow and one in the stern?...I'll have to give it more thought.

I'm really looking forward to this new adventure! I bet it will be outstanding when completed.

Could you just shove a couple of mud motors through those holes and say done? Skip.

Interesting development: The two 15" holes in the transom are not equally spaced from the transom center line...1-1/4" further away on the port side. If anyone is aware of a reason for OMC to have done this other than just a mistake, I'd love to hear about it.



I need to "lower" the holes in order to re-power with the OMC 120's so I'm planning to make the new holes equidistant from the center line.

Look at the transom pic from the inside . you will see that the transom is different on each side it is built different. They moved it over so that the inner ring would have a flat mounting surface. Easyer to move the motors over a bit than rebuild or redesign the transom. I have seen that same thing on some other pics of the same boat using those V-4 motors.I guess they just thought it wouldn't hurt anything any people really wouldn't notice. Might have to rebuild the inside of the transom yourself to mount anything else in there. Skip.

I agree. If the engines were to be mounted in the holes as they are, the engine crankshafts (center lines) would be 10" from the boat center line on the port side, 11-3/8" on the starboard. One of those holes is in the wrong place. I intend to move the starboard hole further away to match the port and give me a little more wiggle room for the engines.

We have the mahogany deck framing in place. All was installed with 5200 in the joints held with stainless steel screws. The entire bilge will be filled with foam floatation even with the top of the framing as can be seen in the engine stringer supports. I have invented a new system for doing this. If it works as planned, I'll publish the method and results. If it doesn't, you'll never hear another word about it!

Good stable platform. My first project in the very early '80's was an Evinrude same vintage. Lots of room to work with the "cab forward" design. I'll be watching your spectacular transformation.
Cal

Nautilus wrote:

If it works as planned, I'll publish the method and results. If it doesn't, you'll never hear another word about it!

Remember I mentioned that I came up with a new system for leveling foam floatation?...Well, forget it!

We've made considerable progress with the dual deluxe...all new decking and custom engine stringers have been installed. Transom holes were moved to fit the OMC 120 outdrive height. "Boxes" on both sides are full to the top with foam floatation to help offset the extra weight of the OMC's. Dual batteries will mount in front of the port side box...storage on the top of both. Everything has been coated with CPES. It was decided to cover the outdrive area with a polished 1/16" thick stainless steel plate. However, the client has called a moratorium on the restoration for now so the boat has been encased in a tarp coccoon and put away for the time being.

You look like you have really been going at it on this build. Great looking work you have done there. To bad about the foam. I got an idea that I may try. Hopefully your client gets back on this build before too long. Skip.

Nautilus wrote:

Interesting development: The two 15" holes in the transom are not equally spaced from the transom center line...1-1/4" further away on the port side. If anyone is aware of a reason for OMC to have done this other than just a mistake, I'd love to hear about it.

I need to "lower" the holes in order to re-power with the OMC 120's so I'm planning to make the new holes equidistant from the center line.

The offset was on all stringer models. I believe they called it the aperture. Why? Not sure except that maybe to compensate for the tilt mechanism?

Now a few observations on your project:

1) The 2 strokes were noisey fuel pigs but not really horribly unreliable.
2) That boat was also available with a V6. I would say the V6 weight would be close to that of 2 V4s. But 2 inline 4s will be heavy. You may have issues with that.
3) The transom seals came in 3 types back then; Round like yours, square and what I call oval. Only the oval is easy to find new. Also, the select trim models had a different oval with more corrigations to allow the engine to move within the hole. Like it or not because of the transom "scallops" in the upper corners you are stuck with the round type.

I realize that the straight 4's will weigh more than a V6 but the outdrives are considerably shorter and I've added a lot of floatation in the stern. At worst, the extra weight of the second OMC 120 will weigh no more than two guys sitting in the rear seat. She may sit just a little squat in the stern when docked but I don't see a problem when underway. Of course, there's always the option of having a fat chick sit on the bow.

The select trim transom seals were almost certainly better but I don't think they're critical. The amount of tilt is not all that much that one of the round seals with 1-1/2" space all around can't handle it. Besides, once the "sweet spot" is found, most people don't fool with the trim.

Concerning the leveling of the foam: A semi-hot putty knife goes through that stuff like butter. I reasoned that a piece of 1/8" steel about 6"x30", sharpened along one edge and heated red hot would do the same and stay flat enough to give us a good surface. We tried it, holding the steel with two vice grips. We had to push like hell to go through the foam and after about 4" of progress, she'd quit. Then we tried cutting the foam straight down every 3" to make smaller sections we could remove one at a time. We tried it over and over...same result. It would have worked if I had two guys working on it for a week. Finally, I gave up and cut the foam level with a 30" piece of a 1" wide band saw blade with really mean teeth. Messy, but effective and accurate.






The Dual Deluxe will be christened "Retro-Rocket." Here's the logo:

Hey Jan, it's great to finally see a Johnson Deluxe being restored on this site. You are doing a first class job on this beauty. I will be watching this to pick up as many pointers as possible for my Deluxe. Thanks for sharing!

Question, which type of stringers are you planning to install? Electric shift?