what color are the decals? Blue? that would be 1982-1983, or Brown 1984-1985.
my guess is you have a 1985 since the serial numbers for 1985 start with 6611886 and go up to A196291
these exploded views may help.
Buy OEM Parts for Mercury Mercury & Mariner Outboard Parts by HP & Liter 7.5HP Swivel Bracket Assembly Diagram
www.boats.net
Buy OEM Parts for Mercury Mercury & Mariner Outboard Parts by HP & Liter 7.5HP Driveshaft Housing Assembly Diagram
www.boats.net
Buy OEM Parts for Mercury Mercury & Mariner Outboard Parts by HP & Liter 7.5HP Bottom Cowl and Shift Linkage Diagram
www.boats.net
the bracket should bolt to the bottom of the cowl if my memory is right.
the friction discs on the steering in the swivel bracket assembly will probably be worn. I made new ones at work out of delrin.