I don't recall seeing any of these motors being setup for direct steering
and throttle. In view of this I would not expect that you will find any
conversion kits available for easy installation.

You could might look for a tiller handle with twist throttle from an older
motor that you could "jury" rig to your motor. A piece of metal could be
added to the shift lever to extend it out further so you can shift easily.

This is going to take a pretty good amount of resourcefulness and the
ability to find the parts you will need, but it can be done if you want to
dedicate the time and effort to it.

You might go to the Antique Outboard Motor site and advertise for a tiller
handle with twist throttle, many older motors had them. I can not picture
one brand being any more suitable than another so what ever you get you'll
have to do some fabricating. They can be located at www.aomci.org

Do you live near KC ?

I have about 105 motors and as soon as the weather warms up I'll be doing
some serious sorting and selling of the excess, so I might come across what
you could use, but it will have to be a lot warmer than it is right now
before I brave the elements! What year is your motor ?

Don Dando