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Ammeter needle jumping around

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Just another LL question. The ammeter on my tractor wasn't working when I got it. The fuse was blown. Afer swapping the fuse the ammeter is showing ~10 but is flopping around like a fuel guage on a gas cap while mowing even though the tractor is just sitting still. Is this normal? How many amps should I be seeing?

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From my experience the answer to your question is yes, this is some what normal. It depends on the battery condition. If the battery is bad or low and in need of charging you should be see a more constant needle when you increase the rpms. Once the battery is close to its regulator setting the needle can jump.

As well this can be a sign that the regulator is about to fail. (more so than the alternator is week). I have seen a wild acting amp meter and I took off the regulator cover and cleaned the points inside. (be carful not to bend or move any points out of the factory settings. I used a peace of emery cloth and lightly run it over the contactors. Blow out all dust, dirt and rust if any from the inside then sprayed the contactors with a chemical contact cleaner). This seem to reduce some of the wild swings in the amp meter.

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My 712H had a similar ammeter, the needle would bounce between + and - when running. Cleaning and tightening the connections at the regulator took care of the problem.

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