I need help! I have a 1972 Silverline boat with a 165 Hp Mercruiser engine and stern unit. Engine serial # 3291531. Stern drive serial #3220751. I need help with the cutout safety switch. The bolt that holds the rocker arm fell out and I can't find it. Can I use any bolt in the hole or is there a special one? If so where can I get one? Also how do you check to see if the spring is too weak on the rocker arm.