Yamaha Tach pegs out at 7000 rpm when key is on

[Franket0870]

Hi guys,

Yamaha pro 50

Had my boat out today and all was well until I started the motor to head back to the boat landing and my Tach pegged out at 7000 rpm. I turned the motor off started again and the same thing happed. What's causing the issue I really don't like operating without a working Tach.

Thanks,

 

[Silvertip]

Send and ground terminals are shorted either at the gauge or sender.