9.9 4 Stroke runs when it feels like it

[fisherrick]

I have a 96 4 stroke johnson 9.9. When it runs, it runs great. Starts on one or two pulls. Other times it gets no spark at all. Have disconnected the kill switch/oil switch connector, no luck. checked all connections at CD box, no luck. Even spun engine with plugs out using drill motor. Gets spark sometimes and starts fine for awhile. Then no spark again. With engine stopped, if I touch tan/yellow oil pressure wire to ground, get a pretty good jolt. Out of Ideas. HELP