You might want to check on the Yamaha accessories. They're at this link:
http://www.yamaha-motor.com/accessories/otb/helm05.html
Outboard Accessories - Helm Gauges
Yamaha's advanced instrumentation is designed to keep you informed about your engine's systems. Accurate information is available to let you fine tune settings to achieve the best overall efficiency and performance for operating conditions.
--------------------------------------------------------------------------------
MULTIFUNCTION OUTBOARD TACHOMETER
The Multifunction Tachometer features face and bezel designed for optimum visibility and long-term durability. Easily set for 2-stroke or 4-stroke use. The easy-to-read LCD digital readout displays:
Engine rpm
Trim angle
Oil level
Warning lamps
Overheat warning lamp
New for '02: Hour meter for trip (resettable) and total operating hours
6Y5-8350T-80-00 $366.38
Click photo for larger image.
--------------------------------------------------------------------------------
MULTIFUNCTION SPEEDOMETER
The Multifunction Speedometer features a bezel designed for optimum visibility and long term durability. Switch on the back of the gauge simplifies fuel sender hookup. The easy-to-read 2-stage LCD digital readout displays:
Speed
Trip
Time
Fuel
Low-fuel warning - flashes on the lowest bar
Battery voltag reading - displays battery output (10-16 volts) and flashes the readout when the output falls below 12 volts
6Y5-83570-S5-00 $366.38
--------------------------------------------------------------------------------
FUEL MANAGEMENT GAUGE
The Yamaha Fuel Management Gauge monitors:
Fuel consumption
Fuel economy (Using speedometer or GPS input for readings)
Fuel contamination (when deluxe Fuel/Water Separator is used)
An engine synchronizer is included for dual engine applications.
Single Engine
6Y5-W0088-53-00 $593.55
Just more things to spend your money on.