Transmission to Shaft Coupler Adapter?

[reka30]

I have a Hurth 250 transmission, with a 4" drive output (Warner pattern; 4 bolts).

The maximum size prop shaft that can be used in a 4" flange coupler is 1 1/2". I have a 1 3/4" prop shaft, which requires a 5" flange.

I need a coupler adapter that will connect the 4" flange on the transmission to the 5" flange shaft coupler.

Anyone know where I can get one?

Thanks in advance for your help.

[scottyt]

you could go to a machine shop and have one made, the only issue would be shaft length. the adapter might be as short as 1 inch, but probably more. the best bet would be to have a custom coupler made for the shaft that takes the larger shaft with the smaller bolt pattern.

cost at least a few hundred, and i would have 2 made so you have a spare. the cost for the second would be cheaper as they would have the setup ready.

[Maine Sail]

I've never seen one or heard of one. Most shafting shops and boat builders try to stay within standard ranges/sizes. A machine shop will likely be your best bet for this adapter just be sure it is machined well and has no run out between faces which could add negatively to any alignment issues. You want this adapter to be "invisible" run out wise. It would be best to get the adapter faced (machined straight) while bolted to the shaft coupling. Of course this requires that the shaft is out of the boat...