RPM Jump

Was driving back to the ramp yesterday and once up on plane I caught out of the corner of my eye that my RPM seemed to jump upward about 2 or 3000. After that it seamed to be just indicating hight because my spead was about 45 mph and my RPMs were about 6000. The motor didn't seem to sound like the RPMs were that high. Normally I am getting about 60mph from about 5500 RPMs. Any idea's or thoughts.

Thanks

Sounds like a bad tach. The tach on my Stratos would do that from time to time.