Hello, we have a Yammie 115 4 stroke, 2005 model and recently the speedometer gauge doesn't want to work. It has been operating fine until the other day. We did get in shallow water and hit a soft mudbar - it really didn't hurt or mar up the lower unit in any way. The speedometer we have on the console is a "Faria" non-digital (regular old gauge-type). From what I understand, there is some type of intake hole on the lower unit that connects to a small dia. soft pipe that then connects to the speedometer. I'm guessing that water pressure activates the speedometer. Could this tube be plugged? What can I do to fix the problem? Anyway, any and all help would be appreciated. The engine runs fine otherwise.
The pickup hole is on the front of the lower unit just above the ball shaped part. It may be hard to see. It can be cleaned out with a very small diameter drill or dental instrument.It's a lousy arrangement, subject to clogging very easily, but Yamaha stays with it. Many people have simply given up on it and relied on their GPS. Pitot type boat speedometers are not famous for their accuracy anyway.
I also have the same problem with my 2011 115hp Yamaha outboard. I used a small drill to clear the hole and all is well. I don't know if I would blow air because it may blow the hose off the nipple in the lower unit.