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    Yanmar Voltage Regulator Problems

    Your Yanmar tractor not keeping the battetry charged? Chances are the regulator is bad. Yanmar uses an extremely reliable "generator" unit that, unfortunately, uses an unreliable external regulator.

    To test the generator you need to use an AC (like a house voltage, not a car) volt meter. Locate the two wires coming out of the generator and follow them to a small plug. After disconnecting the plug, hook the ground wire from the meter to one wire and the posative to the other (it doesnt matter wich one). With the tractor running at a medium idle, you should have either 14VAC or 40VAC (+-). If it is anywhere close your generator is OK. If your generator is broken you will not get any voltage at all.

    Check to be sure that all of the wires look OK from the generator to the regulator and also to the battery. If all of these are OK, your voltage regulator has likely burned out. There is no way to repair these units. You can find replacement regulators here.


    We have a full line of fuel, oil, and air filters in stock, ready to ship. Most orders shipped on same day. Click Here to see our filters.


    Did you find this tip useful? You'll find plenty more like this in our new, easy to read, 35 page booklet "Guide To Imported Tractors". Click here to find out about the book. Don't forget to sign up for our free monthly newsletter with more articles like this by entering your email address in the box at the top left of the page.

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