[KVenom]

Same issue with mine. Turned out to be the worst possible outcome in that the speedo drive gear on the tail shaft of the TKO-600 was bad. The possible cause to this was that the clip that holds the gear to the transmission side of the cable had fallen off. Possible excessive run out of the cable and or gear put wear on the tail shaft gear. I found the clip in the bottom of the tail shaft housing.

Don't ignore it or think you will get to it later. Check everything from gauge to transmission to make sure all is in order.

Mine started with a small bounce at the gauge.