Yamaha Speedo gauge - signal ??

[Bushrider]

Good morning ,
Can anybody advice where the digital Yamaha Speedo gauge take the speed signal from ?
How accurate the speed is displayed ?
On the Yamaha.com / marine section I found something about a speedo kit but nothing at all somewhere in the net how it works or looks like ..
Do not want to install this big gauge just for voltage , fuel level etc
If I decide to go for it I expect everything to work ..

Thanks in advance !

Regards - Jürgen

[jyasaki]

There's a small hole in the leading edge of the lower unit. That hole is connected to a clear plastic tube that runs up to the speedo. As you move forward, the water gets forced into the hole, pressurizing the air in the tube. The speedo converts that pressure to speed.

I find it's generally accurate to within a few MPH as long as the hole doesn't get plugged (it often does, with the result that I rarely look at it.)

jky

[Bushrider]

Hi ,
Thanx for quick respond !
Just been out ( its raining cats and dogs here .. ) and made a pic from the lower case . There is indeed a little opening exactly where the lower / upper unit are connected .
There is also a black hose - which I thought when I changed the impeller some time ago - is the breather for the lower case .
Am I wrong ?

regards - Jürgen

[Bushrider]

Guys - thanks - all sorted out ..
I found the water inlet for the speed . It is a tiny hole which was completely plugged ...

Cheers - Jürgen