would like some info on a johnson 7.5 hp motor serial# 1435940 model# AD-10-M. How old? Is it collectable? What would I have to do to get it running. (the motor is in excellent shape and has spark. Put a little fuel in the cylinders and she fired. The "mile master" gas tank that came with it is gunked up a little so I didn't connect it.) Do I have to use this tank or can I get a late model tank and will it work?