I was fishing this past weekend in my '90 Tracker Deep V, with a 40hp Johnson outboard. After several hours of fishing, I noticed the tachometer was registering much higher than usual. I usually run about 4800rpm with the throttle wide open. I was now hitting the redline at 6000. The engine sounded exactly the same as normal. The top speed was exactly the same as normal. I don't think the engine is doing anything out of the ordinary, just the tachometer. Is there something I can check?
