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  • Post last modified:May 13, 2023
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Sometimes you notice the power of your trolling motor has gone down, and you don’t quite know why. There could be many reasons for this, and today we’ll discuss the most important ones.

Does it feel like your trolling motor got weaker than it used to be?

If your answer is yes, this article is for you!

1. Bad Battery

A battery or batteries should be checked regularly, as they they are the most common cause of the trolling motor losing power.

If you’ve been using a lead-acid battery and it’s hit the 3-year mark, it’s time to replace them.

Have you thought about lithium batteries? They’re really stepping up their game in terms of performance and won’t break the bank these days.

No matter what kind of battery you’re using, there are some handy checks you can do to ensure it’s still in fighting shape for your fishing adventures.

Test the Voltage

After fully charging your battery, wait for 1-2 hours, and attach the voltmeter to test it.

A flooded lead-acid battery should read over 12.7 volts, and for an AGM battery, it should be 12.8 or more volts.

Battery Cell Check

If it’s a flooded lead-acid battery, make sure the cells have enough water in them. You can also buy a battery hydrometer to check the specific gravity on each cell.

2. Bad Connection

This is another common reason resulting in power loss.

Improperly crimped or corroded connections between your battery and the motor typically result in some parts or wires getting hot. This causes unnecessary battery drain and voltage drop, which may seem like the trolling motor is damaged.

If you are near salt water, the corrosion can progress faster and becomes a bigger problem.

Check Battery Terminals, Plugs and Receptacles

Check all connections. The corrosion can make them much less conductive, which means the current can’t flow freely, and you won’t get full power out of your motor.

If a plug or receptacle has any sign of heat or deformation, get a new plug or receptacle and connect as instructed.

Check Wires and Extensions

If you are using a wire extension, make sure it is not undersized, creating excessive resistance and power loss. Check the ends if they are properly crimped and/or soldered.

3. Fouled Prop Shaft

Another common problem of losing power and speed is something tangled around the prop. This will most likely be a fishing line, rope or vegetation, and frequently results in a tripped circuit breaker or a blown fuse. (if you have one, which you should)

If the circuit breaker doesn’t trip, a fouled prop can slow your motor down, increasing the current draw at the same time.

So if you experience a reduction in motor thrust, remove the prop and get rid of any debris you find.

4. Worn Brushes

If your trolling has been used extensively, it is entirely possible that your brushes don’t make good contact with the commutator or are too short and need replacing.

The only way to see in what shape your brushes are is to remove the prop and open the lower unit to investigate. If you’re not comfortable doing it on your own, it’s best to find a trolling motor repair service.

Replacing the brushes is a straightforward process. It’s also a good opportunity to clean the commutator at the same time.

For most popular models, e.g. Minn Kota, you can order a brush kit online.

5. Bad Electronics

If you have a 5-speed trolling motor, it is possible that your speed controller is damaged and needs replacing. Fortunately, a replacement 5-speed switch is easy to find and install on your own.

If your motor comes with a variable speed controller, also known as a digital maximizer, things get a little more complicated and expensive.

Unless you are sure you’re buying the right control board for your motor, it is probably best to find a local repair shop and ask there.

6. Water in the Lower Unit

The damage to the lower unit housing gaskets can cause water to enter and slow down your motor or even shut it down.


These are the 6 most common causes of a trolling motor losing power.

If you know a different reason why that happens, get in touch with us!

Related article: Trolling Motor Speed Chart