I have a 92 EZGO Marathon 36V that speeds up & slows down on its own

Hey fellow cart enthusiasts, I’m in dire need of some advice here. My trusty ’92 EZGO Marathon 36V has started acting like it’s possessed – one second it’s barely moving, and the next, it’s zooming off at full throttle with the slightest pedal touch. I’ve tried fiddling around with what I know, but nothing’s made a dent in the problem. It’s getting to the point where I’m hesitant to even use it, for fear of either a complete stall or an unexpected sprint. Has anyone else wrestled with this kind of gremlin in their cart?


Oh, I’ve been down that road with my old Marathon. Sounds like your potentiometer might be throwing a fit. I replaced mine, and it was like flipping a switch back to normal. It’s a relatively cheap and quick fix, so definitely worth a shot. Hang in there!

Solutions That Worked for Users

Let’s dive into the solutions that have proven successful, with added details and tips to guide you through:

SolutionUsers Who Found SuccessApprox. Cost (USD)Approx. Time Needed (Minutes)
Replace Potentiometer3$20 – $5030 – 60
Check and Tighten All Connections2$0 (if DIY)15 – 30
Replace Controller1$200 – $40060 – 120


  • Golf cart speed fluctuates wildly without input changes.
  • Sudden, uncontrolled acceleration from a stop.

Possible Causes

  • A failing potentiometer sending erratic signals.
  • Loose or corroded electrical connections disrupting power.
  • A defective controller failing to regulate speed accurately.

Solutions with steps

1. Replace Potentiometer

What I Did: Noticed unpredictable speed changes and decided to replace the potentiometer.

Outcome: Achieved consistent and responsive speed control.

Personal Experience: The replacement was a game-changer. My cart now responds predictably to pedal pressure.

Detailed Steps:

  1. Locate the Potentiometer: Find it near the pedal assembly. It’s the component translating pedal pressure into electrical signals.
  2. Safety First: Always disconnect the battery before starting work to avoid shocks.
  3. Removal: Carefully disconnect the potentiometer’s wiring. Remove any securing hardware and take out the old potentiometer.
  4. Installation: Position the new potentiometer, reconnect the wiring as it was, and secure it in place.
  5. Testing: Reconnect the battery and test the cart’s response. Adjustments might be needed to fine-tune the response.

Expert Tip: Pay attention to the wiring connections and ensure they match the original setup. Incorrect wiring can lead to further issues.

2. Check and Tighten All Connections

What I Did: Went through all electrical connections, tightening and cleaning as needed.

Outcome: Improved electrical flow and resolved erratic speed behavior.

Personal Experience: This simple maintenance step brought stability back to my cart’s performance.

Detailed Steps:

  1. Inspection: Start at the battery pack and work your way through to the motor, checking every connection.
  2. Tightening: Use the appropriate tools to tighten any loose connections. Be careful not to overtighten and strip the threads.
  3. Cleaning: Corrosion can be cleaned with a mixture of baking soda and water. Apply, scrub gently, then rinse and dry thoroughly.
  4. Re-Testing: With everything tightened and cleaned, test the cart for improved performance.

Handy Tip: Regular maintenance checks can prevent many of these issues from cropping up in the first place.

3. Replace Controller

What I Did: After ruling out other causes, I identified the controller as the culprit and replaced it.

Outcome: Restored proper and reliable speed control to the cart.

Personal Experience: This was the most complex and costly fix, but it brought my cart back to life.

Detailed Steps:

  1. Identify the Correct Controller: Make sure you get a replacement that matches your cart’s specifications.
  2. Power Down: Disconnect the battery to ensure a safe working environment.
  3. Removal: Carefully disconnect all wires from the old controller, noting their positions. Remove the controller from its housing.
  4. Installation: Place the new controller, reconnect all wires precisely as they were, and secure the controller.
  5. Testing: Reconnect the battery and conduct thorough testing to ensure the issue is resolved.

Expert Tip: Controllers can be sensitive to static electricity. Ground yourself before handling the new controller to avoid damaging it.

Golf Cart Models Where This Worked

  • 1992 EZGO Marathon 36V


Ernie loves documenting interesting facts about golf.

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