Can anyone tell me the proper procedure for replacing the pull rope on a 1966 Johnson 9.5 hp outboard motor? The Model # is MO-12A. I attempted to replace it myself already and wound up damaging the coil spring assembly which causes it to rewind after being pulled. Now that I've spent $65.00 + on replacement parts I want to do it right. No one locally wants to work on one this old. Please give detailed instructions for dummies!! Thanks