I went out today on my 1999 Fiesta Vee 330 and both tachometers were giving eradicate readings. I noticed the RPMs were reading much higher for a given throttle position or speed than usual. What gets me is the engine sound did not match the higher reading at all. At idle, the reading was 2000, yet I can almost guarantee the engine was turning no faster than a normal idle. While cruising on plane at approximately 23 kts the tachs were reading in excess of 6000 RPMs this is normally in the 3500-4,000 RPM range. While trolling along at approx 8 kts the tachs were reading approx 3200 RPMs, normally this is less than 2000 RPM. At no time did the engines appear to be running as hard as the tachometers were reading. Oil pressure and engine temp read normal. Any thoughts?