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Joined: April 3rd, 2012, 1:52 pm
Posts: 3162
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If your going to build something different and unique why not think outside the box. After all once completed there is likely zero demand if you wanted to sell it , so you are building it for yourself.
Case in Point.....a 12 inch midsection...for a transom mounted water pickup setup.
Original thought was cut and wield a 15 inch OMC triple midsection and nitro gearcase for the project. But to gain 3 inches shorter length doesn’t make sense....just raise the motor 3 inches.
Plus those are very valuable to destroy. And the end result doesn’t provide satisfaction.
So thinking outside the box.....first the cost....then what parts from other makes and models would cost less and could be even better.
The powerhead has to be a 56 omc . So the baseplate tuner and top portion of the midsection has to be from a 56 omc.....easy find 56 long shaft midsection assembly...cost is anywhere from free to $100.
The gearcase and lower portion of the midsection....cost, performance and availability....1:64 mercury ....there are lots of them available and they are cheap....use a 15 inch midsection off a 35 - 40 hp twin and the gearcase off 60-70 49 mercury triple. You don’t want the gearcase with the bolt in carrier...use the early version.
Now the tricky part is the omc steering arm....the modified short swivel bracket and clamp brackets
We know that the omc triple steering arm fits the Yamaha Pro 50 swivel bracket. It will fit the other 40-50 Yamaha swivel brackets as well. After shortening the swivel bracket and steering arm for the 12 inch midsection you likely will need a Yamaha single ram power trim assembly.
You need a solution to work the gear shift on the mercury gearcase. It’s a twist to shift. The later model 40-60 mercury cowls have the remote control shift mounted in the lower cowl. That will work. plus the mercury cowl is large enough to cover the 56 omc powerhead.
You use a 2 piece drive shaft....the top portion matches the 56 omc spline. You weld a heavy duty 1/2 socket on the end as a coupler ...the 1/2 drive “square” slot will be the coupler for the mercury drive shaft which you shorten accordingly and square the end to fit the end of the socket.
You want to use the long 56 tuner so the exhaust reaches gearcase otherwise the hot exhaust could damage the water pump cover.
The cleaner the parts the easier they are to weld. You may need to weld strengthening plates inside the midsection at the welded seam.
What do you end up with?
A motor that looks like a 40 mercury, but is actually a 56 omc and with a better performance gearcase compared to a nitro case and it wasn’t that costly a project....added bonus is not too costly to replace the gearcase with another one down the road.....the mercury gearcase is the easiest one to drive on a T boat especially the 12 x 22 cleaver thru hub.
I would bet this setup with an SST 60 powerhead and transom mounted water pickup runs over 80 mph on a critchfield. Imagine seeing a 40 mercury running that fast.
Have I got a few people thinking!!
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