I had a similar set up on a 14 ft Lone Star. That motor should tach at about 5500 rpm. If it is taching that you might try a higher pitch prop to get a little more speed, but it's not going to be fast. It does have a charging system. If it is working you should not need to charge the battery. I believe based on the serial number it is a 1981 motor. As for the steering. It could be the trim tab needs to be adjusted to compensate for the prop torque.
Trim tab is under the anti vent plate just above the prop.
it is a little fin and it needs to be turned to compinsate for prop torque.There is a bolt that holds it loosen the bolt and turn the trailing edge to the left port side of boat.This tab serves as a sacrifical anode too so it could be eroded or missing.You can get a replacement at your dealer.