how to tell if the speedomiter works

jserb

Chief Petty Officer
Joined
Nov 29, 2005
Messages
406
just like the title, i have an older speedomiter, and when i blow into it the needle dosent move, im assuming this is a way to check and see if its in working order. its a water pressured guage, does anyone know if its easy to fix or a way to test it to see if it works!?
 

LubeDude

Admiral
Joined
Oct 8, 2003
Messages
6,945
Re: how to tell if the speedomiter works

I have know idea what kind of preasure is needed to move the needle, but I dont think you can blow that hard without your eyes popping out. :p
 

Pony

Rear Admiral
Joined
Jun 27, 2004
Messages
4,355
Re: how to tell if the speedomiter works

Maybe you could use/borrow a gps and verify your tach against it.......then if it isnt accurate try to fix it.
 

alden135

Lieutenant Commander
Joined
Sep 1, 2004
Messages
1,770
Re: how to tell if the speedomiter works

It does not take a lot of pressure to get the needle to move.
 

Chinewalker

Fleet Admiral
Joined
Aug 19, 2001
Messages
8,902
Re: how to tell if the speedomiter works

It does on my old Keller speedo. Of course, it STARTS at 45mph!<br />On a standard speedo you should be able to at least budge the needle with breath pressure. I think my brothers and I busted a few blood vessels when we were kids trying to outdo each other blowing into one of those things...<br />- Scott
 

KRS

Banned
Joined
May 15, 2004
Messages
2,383
Re: how to tell if the speedomiter works

Use a can of compressed air, like you'd clean a computer with.<br /><br />Or a regular compressor.<br /><br />If using either of these, then be sure you don't blow full force, just direct air across it until you see movement. I can get mine up to 45 mph with a can of compressed air blowing into the hole.<br /><br />If it isn't budging, then the pitot may be clogged, or the tube taking the pressure to the gauge is cracked (leaking), or the gauge is bad (the last probable reason).
 
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