A trolling motor propels your boat through calm waters. It provides stable speeds and directional control for fishing or slow cruising in lakes, rivers, and other calm bodies of water. Like all mechanical components, these motors can wear down with time and usage. This deterioration can lead to various issues, with power loss being one of the most frustrating problems anglers face.
If you notice your trolling motor losing power, several common causes could be at play. To address this issue, you’ll need to identify the root problem first. Here are some of the most common reasons your trolling motor might be underperforming, along with practical solutions to get you back on the water.
Dead or Weak Batteries
Battery problems are the number one culprit behind trolling motor power loss. Your motor relies entirely on battery power to function, so performance drops when batteries start to fail.
Weak batteries often develop gradually. You might notice the motor runs slower than usual or struggles to maintain a consistent speed. Cold weather can also temporarily reduce battery capacity, which causes this problem to become more noticeable during cooler months.
Check your battery voltage with a multimeter. A fully charged 12-volt battery should read around 12.6 volts when not under load. If readings fall below 12 volts, your battery needs charging or replacement. Clean any corrosion from battery terminals, as buildup can create resistance and reduce power transfer. Also, test your batteries under load to get an accurate picture of their condition.
Corroded or Loose Connections
Poor electrical connections can reduce the power reaching your trolling motor. Corrosion, loose bolts, or damaged wiring all contribute to this problem. Water exposure makes corrosion almost inevitable on boats. Salt water accelerates this process, but even fresh water can cause issues over time. Corroded connections create resistance, which reduces the electrical current flowing to your motor.
Check all connections between your batteries and motor for any issues. White, green, or blue buildup around terminals and connections is a sign of corrosion. Use a wire brush and a solution of baking soda mixed with water to clean corroded areas. Tighten all connections, and don’t overtighten in order to avoid damaging threads or terminals.
Damaged Propeller
The propeller transforms the motor’s rotational force into thrust. Damage to this component can cause power loss and poor performance. Fishing line, weeds, or underwater obstacles can damage propeller blades. Even small nicks or bent areas can reduce efficiency. A completely clogged propeller with weeds or debris will bring your motor to a near standstill.
Remove the propeller and inspect it carefully. Look for bent, cracked, or missing blade sections. Remove fishing line wrapped around the shaft. Minor damage might be repairable, but severely damaged propellers need replacement.
Motor Brush Wear
Brushed trolling motors use carbon brushes to transfer power to the motor’s commutator. These brushes wear down naturally with use and can cause power loss when they become too worn.
Worn brushes create poor electrical contact, leading to reduced power and erratic performance. You might notice intermittent operation or the motor stopping unexpectedly. Spark formation around the brush area can also indicate wear issues.
Most trolling motors allow brush replacement, though the process varies by model. Check your owner’s manual for instructions. If you’re not comfortable with electrical work, take your motor to a qualified repair shop.
Internal Motor Damage
Sometimes the motor’s internal components suffer damage that affects power output. This might include worn armatures, damaged windings, or bearing problems.
Internal damage could result from overuse, water intrusion, or age. Motors subjected to heavy loads or operated in harsh conditions face higher risks of internal problems. Strange noises, excessive vibration, or burning smells can indicate internal issues.
Internal motor repair typically requires professional attention. The cost of rebuilding might approach the price of a new motor, so consider all options. If the motor is old or has undergone multiple repairs, replacement might make more sense financially.
Wiring Problems
Damaged or undersized wiring between the batteries and motor can restrict the flow of electricity. A wire gauge that’s too small for your motor’s current draw creates a bottleneck that limits performance.
Heat, vibration, and moisture can damage wiring over time. Undersized wires may work initially but create voltage drops under load. This voltage drop reduces the power available to your motor, especially at higher thrust settings.
Inspect all wiring for cuts, fraying, or heat damage. A wire gauge chart can help you confirm that your wiring meets your motor’s requirements. If you find damaged sections, replace them with marine-grade wire of the appropriate gauge. Upgrading to heavier gauge wire might be a good idea if your current setup isn’t up to snuff.
Speed Control Issues
Digital and variable speed controls can malfunction, limiting the power sent to your motor. These electronic components can fail due to moisture, corrosion, or component wear. Speed control problems often appear as erratic operation, inability to reach full speed, or complete loss of control. Some units may work intermittently, making diagnosis challenging.
Test your speed control by bypassing it temporarily (if safe to do so) and connecting the motor directly to the battery. If the motor works normally, the speed control needs repair or replacement. Moisture protection for electronic components can prevent many speed control failures.
Overheated Motor
Trolling motors can overheat when worked too hard or when cooling systems fail. Overheating triggers thermal protection that reduces power output or shuts down the motor completely. Luckily, heavy loads, shallow water operation, or blocked cooling vents can cause overheating. Some motors have built-in thermal protection that automatically reduces power when temperatures rise too high.
Let the motor cool completely before restarting if it overheats. Inspect ventilation areas for blockages and remove any debris. To reduce the load on the motor, adjust your speed or avoid operating in extremely shallow water.
Get Back to Full Power
When you understand the cause behind your trolling motor losing power, you can address the problem. If you determine that battery failure is the cause behind your motor’s poor performance, PowerHouse Lithium has your back. We sell lightweight and powerful lithium trolling motor batteries. Explore our selection to find the right battery for your boat, and get back to making the most of your time on the water.