Question about fixing the tachometer

[vlmuke]

When I bought my duece two summers ago the tach was broken Is this a common problem is just a bad cable od could it be the gauge any thought or experinces would be apreciated since I am going to be fixing the injector pump might as well fix it too
Thanks
Rich

 

[gimpyrobb]

Easiest way to find out is to remove it. My cable was snapped at the input of the gauge. A quick swap out of the cable fixed it. Do not let that statement fool you, it will not be quick.

 

[m-35tom]

best way is to look and see what is not working.............

 

[MilitaryRestoration]

question that kind of pertains to this one...and good place for it...how do you reverse the cable...mine is running the tach backwards the way i can tell is thought that the old one was broken so put a new one in and the hour meter is now in low 9000's

 

[acetomatoco]

It the new tach a direct replacement? Some tachs run in opposite directions, due to engine rotation. Thinking of GM Diesels for example... There is a mil spec tach on Ebay right now from Boyce Equipment, but if you look at it you can see that it is a 0-6000 rpm... most of our stuff is 0-4000. I would look at the drive gear in the transmission/transfer (for speedos) and in the front of the engine (for M/F Deuces) and in the Distributor (for M5 Cadillac Tanks )and see if it is the correct one. You cannot make a cable go in the opposite direction, but you can apply rotation to it in the opposite direction. It only transmits what it sees on one end, to the other. In this case, I would suspect the drive gear. To test your tach, take it out.. takes about 3 minutes, and stick a pencil in the square drive end and twiddle it around, the needle should bounce up and down as you do this... is a good quick test, but of course does not prove the hourmeter portion to be working....you can also do it with a slow speed electric screwdriver with a square bit...SLOWLY.

 

[MilitaryRestoration]

ya i pulled the tach and spun it and it does work but then when i put it into the truck it operates backwards...so like you said it must be the drive gear. i'll have to pull it apart and see whats up. if it is the drive gear does anyone know what needs to be done. do i just reverse it or do i need to find a new/different one?

 

[m-35tom]

you need to test the tach to see what direction it runs. looking at the back of the tach, the drive should turn anti-clockwise. looking at the cable end it should turn clock wise

 

[emmado22]

the drive should turn anti-clockwise

also known as counter clockwise....

 

[m-35tom]

have never heard that used

 

[acetomatoco]

as I am an old guy, I have heard both the terms... Now let's hear it for "foot feed"

 

[steelandcanvas]

as I am an old guy, I have heard both the terms... Now let's hear it for "foot feed"

"Foot feed" is an old tractor operator's term for an accelerator pedal. My Dad uses this term all the time, wasn't until I started reading about old tractors, that I figured out what he was talking about. I always thought he was saying "foot feet", what the heck's a foot feet??

 

[timb1956]

how do you get the broken tip out of the back of the tach? My new cable
won't seat all the way and i am assuming tip is still inside

 

[big1096]

When I got mine the tach wasn't working either. After pulling the cable I found that it wasn't broken, but it was rusted into the drive adapter on the engine. The angle drive was rusted solid and broke the shaft pin in the engine. That was a fun replacement there.... It works now. I'm glad I have a parts source close by.