You are here:

Small Engines (Lawn Mowers, etc.)/Lawn tractor won't hold charge


QUESTION: I inherited an MTD Yard Machines rider a few years ago, 16.5 HP Briggs. It runs fine when I can get it started. I replaced the battery right away 3 years ago when I got it, but that didn't seem to matter. I still needed to charge it every time I wanted to start it. It seems like the charge is lost even after a day or so. It will also act weird if I stop the motor in the middle of my chores. I go to start it sometimes, and it's just dead. Won't turn over. Seems like I have to move the machine manually a bit and play around with locking and unlocking the brake, put the charger on, etc. to get it started. Not sure if this is doing anything, but eventually it seems to get going again. Temperamental! Got any ideas? I would greatly appreciate your help.

ANSWER: I recommend reading the link below to identify and test your alternator/regulator.

I would also charge and have the battery load tested at you local autoparts store.

If you charging system is working then the next time you park the mower I would dis-connect the negative battery cable after you are finished using the mower.  Re-connect the battery when you need to use the mower again and see if it starts...make sure the battery is fully charged when you dis-connect it.  This will help determine is something is draining the battery when you park the mower.

You can also dis-connect the positive cable when the mower is parked and connect a meter between the positive battery terminal and the cable.  If the meter more than 1 volt there is something draining the battery.

Let me kwnow what you find.

---------- FOLLOW-UP ----------

QUESTION: Sorry Eric for the very delayed response to your kind and timely response to my question. I bought a new lawn tractor so I have let this one sit for the past 2 months up until now. I am fixing it up to sell it and am still having problems. I just went ahead and bought a new battery, but having the same issues where it doesn't seem to hold a charge and in fact doesn't seem to have enough cranking amperage or something to crank it over. I went to the Briggs and Stratton alternator link you provided but it is just too technical for me to figure out how to test the alternator and I don't have the meters anyway. What do you think. I talked to a guy in my community who works on riding lawnmowers and he told me to take off the negative battery cable and if the engine still ran, it was likely the alternator. It did still run. Like I said, I bought a new battery and I'm still having the same problem. What do you think? Is it worth it replacing the alternator? Is it a job an amateur like me can do relatively easy? I am selling it after all and obviously don't want to spend much to fix it. I really do appreciate your help. So kind of you to take the time to offer ideas.

No, dis-connecting the negative cable when it't running will not really tell you anything.  You really need a meter to check the charging system to see which part(s) are bad.  It is very expensive to just replace the stator not knowing if it is working or not.

Harbor Freight and many home repair stores sell inexpensive meters.  One of the cheaper meters will work find to test the parts.

I would not recommend just replacing parts.


Small Engines (Lawn Mowers, etc.)

All Answers

Answers by Expert:

Ask Experts


Eric A. Jones


Lawnmower Repair . Certified Master Service Technician from B&S. Have 23 years experience on B&S, Lawn Chief, Weed Eater, Echo, Peerless, Wheel Horse, Snapper, Atlas, MTD, McCulloch, Homelite and many other numerous brands. Specialize in electrical repair.


Born and raised in the midwest. Started tinkering with engines when I was about 14 on my Suzuki RM-80. I began lawn mower repair at a small hardware store. I knew absolutely nothing. I read lots of repair manuals and met an older fellow who taught me many lessons. I continued working on small engines through high school and paid my way through college working on mowers at the same hardware store. Decided to get away from the midwest and mower repair so I joined the Air Force. I repaired air traffic control electronic equipment and ended up in Hawaii where I got a part time job at Small Engine Clinic. I gained a lot of experience from the Small Engine Clinic and had a blast repairing small engines. I then took the Briggs and Stratton Master Service Technician test and earned my MST. I then traveled to Wisconsin where I attended the factory update training seminar and received formal training. Continued working on mowers part time as I completed 20 years of military. Retired from the military on a Friday and continued in the lawn and garden industry the next Monday.

MAS Aerospace Operations BA Mathematics AAS Electronic Communications AAS Electronic Technology

©2016 All rights reserved.