Champion J6C
Champion J6J is the recommended plug which has been changed to J6C by Champion.
For a 1970 OMC 6HP engine, the recommended spark plug is the Champion J6C or an equivalent plug
The correct spark plug for a 1963 Evinrude 10hp outboard is typically a Champion J6C or equivalent. The recommended spark plug gap is generally around 0.030 inches (0.76 mm). Always consult the owner's manual or a trusted source for specific details related to your engine model.