Speedo Not Working

Acer2428

Petty Officer 3rd Class
Joined
Aug 6, 2007
Messages
82
Hey all:

I just bought this boat. It's got an '81 (I assume it's orig) 115 Merc on it. Not pitot tube to replace. Which tube is it that leads to the outdrive?

What should I check?

Should I just go to a pitot setup?

Thanks,

Sam
 

Silvertip

Supreme Mariner
Joined
Sep 22, 2003
Messages
28,771
Re: Speedo Not Working

A speedometer is simply a pressure gauge that's calibrated in MPH. It has a small diameter tube on the back that runs back to either the pitot on the engine (if it has one) or to a separate pitot. It's apparently disconnected at the engine or pitot, or the tube is pinched somewhere along the line. If it had a hole in it or was disconnected from the speedo your feet would be getting wet.
 

Acer2428

Petty Officer 3rd Class
Joined
Aug 6, 2007
Messages
82
Re: Speedo Not Working

Well the boat hasn't been in the water yet! lol. It supposidly has no leaks. I guess I'll just have tot race the line and see if it's connected?

If it is, try blowing in it? Will I be able to generate enough air pressure with my mouth if it's functioning normally?

If there's a clog, what's the best way to get it out, compressed air?

Thanks.
 

Acer2428

Petty Officer 3rd Class
Joined
Aug 6, 2007
Messages
82
Re: Speedo Not Working

The line appears to go into the lower unit.

What's my next move?

477A5B1D2D75493F81169106C513B085.jpg
 

Blue Water Runner

Petty Officer 3rd Class
Joined
Jul 11, 2006
Messages
87
Re: Speedo Not Working

Take a very small drill bit and stick it in the hole in the lower unit inlet. You may have to turn the bit by hand to clean out the hole. You can also blow it out from the other end with compressed air. I just cleaned mine out.
 
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