Ford 3000 Tach not working

   / Ford 3000 Tach not working #1  

Laneman

Bronze Member
Joined
May 22, 2007
Messages
64
Just looking for a step by step guide to find out why tach doesn't work. I do have a generator and cable is hooked up to gen. I unhooked cable from gen and turned it by hand. Noticed some tach needle movement but it seems to move erratically and stick at different numbers. Movement of needle does not seem normal in relation to turning the shaft. Was thinking of spinning cable end with a cordless drill to check for needle movement. Any risk of damage with this method i.e. if I turn it the wrong way? Any better ways to test?
 
   / Ford 3000 Tach not working #2  
I think the cordless drill is a perfect idea and will tell you if the cable and tach head are working properly. Your cable might be binding and twisting, then releasing with a surge, so be careful. If it hasn't worked in awhile, the tach could be a bit stiff and jumpy, but should smooth out rapidly. It could be the gear in the generator driving the cable or a stuck cable that caused the generator wormdrive gear to fail. Your using the drill as a first test seems like a logical step to me.
 
   / Ford 3000 Tach not working #3  
The only thing I can add is to take the cable off from either end and try to rotate it by hand pressure to see if it is bound up or not. Then take some lubricant and put a few drops from top and rotate the cable by hand and then I would do the drill test. That way you can not damage the cable during your drill test.

JC,
 
   / Ford 3000 Tach not working
  • Thread Starter
#4  
The cable rotates good by hand. The tach needle moves some, but seems to get stuck even though the cable is still turning. Seems like an issue with the gauge itself. I don't know how they work, but it seems like something is slipping inside the gauge.
 
   / Ford 3000 Tach not working #5  
If it is like other tachometers I have taken apart, they involve magnets and fairly small tolerances. It sounds like a small piece of iron has gotten in there. If you want to try to fix it yourself, a needle (steel, one that will stick to a magnet) point can pick up the piece if you can find it.
 
   / Ford 3000 Tach not working #6  
Tachs operate on principle of counting pulses (electrical), a magnet crossing a coil can cause a mag field on a coil. the number of the time filed collapses can be used to correlate to engine rotation. tachs are cheap, i's open it up and try to clean and look for foreign object in there. Might be able to use a HF cheapo tach or go to Napa. I'm sure they can match you up something. can verify and calibrate using a timing light in case of a gasser or an optical tach or light strobe tach.

JC,
 
   / Ford 3000 Tach not working
  • Thread Starter
#7  
Today I verified that the cable turns at the generator end. I unscrewed it and lifted up slightly while tractor was running and could see the cable turning. I'll try to open up the tach itself. Thanks for the help.
 
   / Ford 3000 Tach not working #8  
Tachs operate on principle of counting pulses (electrical), a magnet crossing a coil can cause a mag field on a coil. the number of the time filed collapses can be used to correlate to engine rotation. tachs are cheap, i's open it up and try to clean and look for foreign object in there. Might be able to use a HF cheapo tach or go to Napa. I'm sure they can match you up something. can verify and calibrate using a timing light in case of a gasser or an optical tach or light strobe tach.

JC,

the 3000 cluster tach is purely mechanical.. no pulses or anything.. just gets driven off the genny..or the aux drive location if available.

soundguy
 
 
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