1974 Johnson 135 HP Outboard Motors Service manual, Page 96Get this manual
7-4 Install the batte ry near the molo rFor mounting the battery, use Coast Guard approved battery box (available as an OMC accessory) securely fastened to the boatA loose battery may shift in the boat, damaging itself or other equipmentTighten hold- down nuts evenly until batte ry is secureIf hold-down nuts are too tight, distortion and damage to battery case will result REFEREtlCE PICTURE