I have a 1968 55 hp Johnson that i am trying to get running again. The engine/boat was a family members that let it sit idle for many years. I have replaced the wiring,and have a new battery, it cranks over great, but while cranking it has no spark, but the second you let off the starter (key still in "on" postion), it starts to spark, and occasionally will even catch a cylinder. I bypassed the ignition key to the starter thinking that there may be some kind of short in the switch causing the igniton system to ground out, but i had the same results. With the key on, I can manually advance the flywheel and get spark, but again, not while cranking under battery power. Any suggesstions on where to look next would be greatly appreciated.