Just changed the oil in the motor at 100 hour period. While I mostly use the motor for trolling I give it full throttle moving from place to place. After I changed the oil I pull the hand chord 8 times to move the fresh oil around. While going the lake yesterday morning I had the trottle wide open and the oil light came on. This was running wide open for about a mile and half. I immediately shut it down and pulled into shore and checked the oil gauge. It was just below the full level. I let it sit for a while and started it back up and no light, as long as I kept the trottle at half I would get no light. I gave it full throttle once while putting the boat on the trailer and the light came back on. Any one have any ideas?