How to Fix a Boat Voltmeter

Boat motors that use an electronic ignition system require a battery to start the engine. A vehicle's voltmeter is the instrument that measures the level of battery charge. If the meter is faulty, the boat could be unable to start, and get stuck in open water. A marine repair shop can fix a faulty voltmeter but the cost can be high. You can use a few professional techniques to fix a boat voltmeter, saving the cost of hiring a repair.

Things You'll Need

  • Rags
  • Screwdrivers
  • Cotton swabs
  • Rubbing Alcohol
  • Electrical tape
  • Compressed air
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Instructions

    • 1

      Disconnect the boat's battery. Never work on a boat's electrical system while the battery is connected. To disconnect the battery, access the battery compartment and carefully remove the red and black battery cables. Wipe any corrosion off the battery terminals and cable clamps with a rag.

    • 2
      The screwdriver should fit tightly into the screw's head.

      Access the voltmeter. Most voltmeters are attached to the instrument panel with set screws mounted to the panel's backside. To access the voltmeter, use a screwdriver to remove the protective panel by unscrewing the mounting screws located on the front or sides of the panel. Flip the panel over to expose the back of the gauges.

    • 3

      Use a screwdriver to remove the voltmeter's mounting screws. Remove the voltmeter from the panel by turning its casing left to right. Over time, corrosion can cause the gauge to stick to its mounting panel. Therefore, it should not be pulled out by force. Allow the voltmeter to hang by the two wires leading out from its backside.

    • 4

      Inspect the wiring. Corrosion is the biggest problem with boat electronics, creating a barrier that resists the flow of electricity. Look for physical damage to the voltmeter's wiring, such as crimps and tears in the shielding. Examine the wiring terminals for corrosion on and around the soldered terminals.

    • 5
      Only use electrical tape to cover inshielded wiring.

      Clean the wiring. To remove the corrosion, dip a cotton swab into rubbing alcohol. Squeeze out the excess liquid. Gentle rub the corroded surface with the tip of the swab until the corrosion is removed. Cover any unshielded wiring with electrical tape.

    • 6

      Check the voltmeter's needle. The needle acts as an indicator for the amount of electrical charge in the battery. The needle is mounted to a small shaft that allows it to move back and forth. If the shaft is clogged because of dirt and corrosion, the needle will not function correctly. Look for corrosion on the front and back of the needle.

    • 7
      Use the tip of the swab to clean off any corrosion.

      Clean the needle using compressed air. Place the tip of the nozzle above the gap between the voltmeter's casing and the needle's base. Squeeze the nozzle down and allow the air to flow for 60 seconds. Use an alcohol-saturated cotton swab to clean off any remaining corrosion.

    • 8

      Check the wiring harness connection points. The two wires leading out from the voltmeter connect to the boat's main wiring. Follow the two wires to their connection point. Check the wires to ensure that they are firmly attached to the main wiring or wiring harness.

    • 9

      Replace the voltmeter and reassemble the instrument panel.