Re: Yamaha Analogue Speedo Adjustment
Re: Yamaha Analogue Speedo Adjustment
No replies in 24 hours; I'll take a shot.
This isn't an electrical issue.
Boat speedometers are actually pressure gauges driven by dynamic water pressure impacting the end of the pitot tube on the stern.
The amount of pressure generated below 10mph is minuscule.
Many gauges do not indicate below 10mph.
Are you certain it is out of calibration?
Attach a short piece of tubing to the gauge for test purposes.
If you suck on the tube does the gauge return to Zero?
Applying pressure to the tube can confirm the calibration.
Note that the pressure is exponential and not linear.
The center of a 60mph speedometer will be at 43mph, not 30!
For your Reference...
1.5 psi = 10 mph
2 psi = 12 mph (Typical pressure produced by a set of health lungs.)
6 psi = 20 mph
13 psi = 30 mph
23 psi = 40 mph
52 psi = 60 mph
100 psi = 83 mph and Damaged Speedometer and Hoses!
Assuming the needle has slipped; Crazy idea follows!
If you can carefully adjust the pressure to have the needle hit the stop above the high end of the gauge, you may be able to get it to slip back to where it belongs.
