Speedometer repair

[Hydra Sport]

Ok to start out I know the easiest and most accurate way to measure my speed is to use the gps BUT it annoys the heck out of me when something that should work doesn't SO can anybody tell me what to do to get my speedometer working again and what to do to make sure it stays that way.

[Scott K]

What is the speedo not working on?

[Valv]

On a boat, ATV, car ? What is it ?

[Hydra Sport]

Oops sorry. I was asking about the speedo on my boat.

[Outfitter17]

Did you check the intake hole on the motor to see if it was pluged?

[heat checker]

Mine had come off under dash.

[Outfitter17]

I have had that to, but I noticed it right away because water was spraying everywhere.

[marine_man]

Do you still have a 115 Mercury?

If so, take a look at the leading edge of the lower unit for a small hole - is it plugged with wood, debris, etc?

Take an air compressor and lighly blow into that hole and watch your speedometer - does it move? If not the hose is pinched somewhere between the motor and the speedometer - follow the black plastic hose from the motor to the front and watch for kinks or zip ties that are too tight.

marine_man

[Matt C]

I have the same issue. Speedo not working. Needle is at 65mph at idle speed, and off position. It moves but is off by 30 mph.

Checked hose. Used the compressor and blew air from the hose at the speedo, water came shooting out so its clear.

Is there a way to reset the needle?

Mine isnt a Merc, its a 150 yami 4 stroke.

[Matt C]

Scratch that,I found my issue. Pulled the speedo, looks like the 'calibration' screw fell out.