Dash board speedometer accuracy

[starkyb]

Does anybody out there know how accurate the speedometers are that work from a small hole in lower unit are? My 1998 Tracker V17 registers about 36 mph @5600 rpm with my 75 horse Mariner. My gps stopped working so I'm not sure how fast I am actually going

 

[JB]

Re: Dash board speedometer accuracy

They will get you in the ball park, but don't bet any money on them.

 

[Scott Danforth]

Re: Dash board speedometer accuracy

ski boats are the only installation I know of that have calibrated speedometers, and they are only calibrated for the 20-30mph range.

at best, assume its approximate.