MTD Mower Will Not Hold a Charge

I have a MTD Pro 15.5 hp riding lawnmower that will not stay charged. The battery is new and once charged the mower will run until shut off and will then need to be re-charged. Any suggestions/comments?


By sdokis from Ontario

June 28, 20100 found this helpful

My John Deere does the same thing. So I bought a charger for 50 bucks at a auto supply store. Now a couple of hours before I mow the grass I hook up the charger. If it is still sluggish I put the charger on boost and have my lady disconnect the charger after the mower starts. Crappy but it works for me.

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April 29, 20110 found this helpful

Our John Deere mower does the same thing!

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June 10, 20150 found this helpful

Check the part called "Protection Wire Loop". This nothing more than a diode (P/N 1N5404) that allows the stator (unless your model has a full blown alternator) to send one half of the a/c electrical signal (IE: just the positive part of the the alternating current (a/c) sign-wave) back to the battery to charge it. It's a simple way for getting "dc" voltage from an ac source and therefore recharging the battery. IF the diode is bad the battery can't be recharged.

Look at a wiring diagram for your mower and it will probably be labeled something like "Charging System Output." It may even state the rating - IE: 3 Amp @ 3600 RPM.

The diode on my mower (Craftsman 16HP LT-1000) was located in the wire harness on the right side at the back of the engine. Trace the wire coming from under the left side of the flywheel around the back of the engine. Begin to open the wire harness just before it joins into the main harness. You will find the diode spliced into a wire. The diode starts the split so that one wire (the continuous one) runs the lights and the diode goes to recharging the battery. The diode will likely be broken and literally fall apart.

It's a cheap (maybe as little as 10 cents) if you can find someplace that has them. Or I ordered one online for a few bucks. It's an easy cheap thing to check for a fix. The diode used had a part number of 1N5404. Hope that helps someone. Good luck.

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September 20, 20150 found this helpful

After you're done using your mower turn it off and raise the seat up and leave it up. Pop had the same problem until he tried that and it works.

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July 30, 2011 Flag
0 found this helpful

I have a 16.5hp MTD riding mower and the battery keeps being drained. We purchased a new battery. As soon as we put it in we had to jump it off. Now it won't even jump off. This is only the second time we have tried to use it since the new battery was installed, 2 weeks ago!

By Michelle

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July 31, 20110 found this helpful

1. I would have the battery checked to see if it indeed drained.

2. What kind of engine do you have.

Reason I ask is I have a John Deere L120 with a Briggs and Stratton engine and it would not start. I though it was the battery. I had it checked at a battery store and they told me it had a full charge. They told me there may be an open ground on the mower. I bought a new battery with more cranking power. I installed the new battery and not even a burp from the engine. I asked a JD dealer what could be the problem. He said the valves were out of adjustment. ( Two dealers have told me the same thing.) He explained I had a Briggs and Stratton engine and they have made junk engines for the past 10 years. He gave this bit of information for me to try. On the top of the engine is the air intake screen. With your hands move the screen in reverse or counter clockwise until you have resistance to the turning. Stop and try starting the mower. It worked for me. So every time I want to start the machine I have to counter turn the air screen untill I feel the resistance. Then it starts. As for the open ground,I checked all the connections as well as the safety connections and found nothing. Maybe this will be of some help for you.

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October 9, 20160 found this helpful

You saved me! Thank you!

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