This hynautic k6 rams bolt to the front of your motor (and don't use the tilt tube at all). They work with seastar lines/helm and you can easily put a set together for that price. If you don't want pull the boat out of the water . . . just use a sawsall and cut the old steering out in pieces and buy one of these setups.
http://cgi.ebay.com/ebaymotors/Hynau...ssoriesQ5fGear