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Boat Lift Motor Troubleshooting Guide


When troubleshooting your boat lift motor and it just doesn’t start, make sure that electricity can actually get to it! The most common reasons behind your motor not getting any power, are flipped breakers (or GFCI) and damaged wires.

If your motor starts, but does NOT run and gives you a “humming” noise, this could indicate a problem with a bad start capacitor or centrifugal switch not engaging. There is a chance that the centrifugal switch is simply dirty and needs cleaning.

The following video can give you more information:

If your motor can run but keeps on tripping the circuit breaker, check your voltage with no load and see if there is a short circuit someplace. You should ask for professional assistance to locate a short.

You might have a problem with a motor rotating in one direction only and this could mean that you have a problem with a drum switch. In this case, check for corrosion or loose connections between the motor and a switch.

If you are dealing with a burned motor, the problem could be that you overloaded your lift or your 220/230-volt motor was connected to the 110/115-volt electrical service.

Here is how you rewire your motor for 110-volt service:

** Warning! If you are not sure about what you are doing, just get yourself a drink and ask a professional for assistance. This is not a DYI project and working with electricity is dangerous!

Case #1. My boat lift motor doesn’t start

Your boat lift motor will not start for one simple reason, NO POWER coming through! Why would this happen? There could be several reasons:

  • Your breakers are flipped.
  • A wire is cut someplace.
  • Contacts developed corrosion or got loose.

Here is what you can do:

  1. Check if your motor is plugged in.
  2. Check if the power is supplied to your outlet.
  3. Check if your breakers or GFCI are reset.
  4. If none of the above work, ask a professional to check your wiring.

Case #2. My motor starts but does not turn

If your motor is making a humming noise, this generally means that either your capacitor is out of order or the centrifugal switch is not doing its job. Single-phase electric motors use start capacitors to energize a second-phase winding.

Some other signs of a bad capacitor include bulging, cracking, leaking, and burned terminals. Here is an example of a capacitor:

Some starting capacitors feature a bleed-through (or bleed-down) resistor:

Any single-phase induction motor needs some kind of reactive power to provide a phase shift, so the motor will start rotating on its own. This is where capacitors come in.

Did my capacitor go bad?

In general, capacitors fail when the motor starting relay gets stuck closed for a longer period of time than it should. If the capacitor gets overheated or has an internal short (due to moisture buildup, for example), you will need to replace it.

It is also a good idea to check your motor starting relay for problems before it damages a new capacitor. When choosing a capacitor for a replacement, go for the better quality one if you want the best performance from your motor.

How to change a capacitor? When changing a capacitor, try to use exactly the same as the previous one. If you need to get a different type of capacitor, make sure:

  1. Its voltage rating is the same or higher. The higher the rating, the more voltage it can withstand. They have thicker walls and better insulation, which also means greater longevity.
  2. MFD, MF, or UF (μF ) rating is the same or up to 12% higher. All these letters mean – “microfarad”, which is a capacitance rating.

Also, make sure that you are getting a start capacitor, and NOT a run capacitor! Start capacitors are bigger in size and have a plastic shell. Run capacitors are usually enclosed in metal cases that are filled with oil to help dissipate the heat.

Sometimes run capacitors can be used as start capacitors, but not the other way around. There is also a difference in terminals:

The following has to be done with a motor disconnected from the live energy source. Once again, if you are not sure what you are doing, ask for professional assistance!

Before removing a start capacitor, don’t forget to short it out by touching both terminals with a screw or nut driver (with a plastic or rubber handle). Be very careful and for more protection use gloves.

Shorting could create an arc or a spark, so don’t have anything flammable nearby. Once discharged, now you can remove the wires.

How to test a capacitor? You will need a multimeter that will do capacitance (here is a fairly inexpensive one from Amazon – paid link). The symbol, that you need to select on the multimeter is this one:

If you get no measurement or OL (multimeter overload), that means that your capacitor is out of shape and needs to be replaced. If you get a reading that is within the minimum and maximum capacitance range (as stated on the side of the capacitor), then your capacitor is fine.

Centrifugal switch is responsible for energizing start windings (or coil) until a critical RPM is reached (about one-half from the normal motor speed).

After that, it disconnects the start capacitor with a clicking sound. Here is where this switch and a start capacitor are located within a circuit:

If the centrifugal switch is unable to close due to dirt buildup, you will only hear a humming sound and the motor will not start. This is what it looks like:

How to know if you have a capacitor problem? If you try to spin the shaft yourself and it starts working, the problem is most likely to be the start capacitor. Make sure that you DON’T spin the motor with your hands (you can try spinning the motor fan with a stick)!

Here is a good video on troubleshooting a start capacitor and centrifugal switch:

What if the motor is stuck?

If your motor cannot be turned manually after you removed it from the lift, it’s “done” and it needs to be replaced. You can troubleshoot the motor while it’s not on the lift by checking its gearbox for problems (it could be stuck).

Drum switch problems?

Another reason for the motor not turning when powered ON could be incorrect wiring to the drum switch.

If your motor can start motor manually, that means that something is wrong with the power being delivered to it. Check for corrosive connections on both sides.

Your motor could also be burned out!

Open the motor access plate and check for burn marks inside. Make sure that you disconnect it before doing so!

In this case, you will need to get a new motor.

Case #3. My boat lift stops

This problem occurs when not enough electricity is supplied to the motor and it is especially true when the boat is being raised up. When more amps are used, fewer volts are available.

Your boat lift system needs to maintain a constant voltage to work properly. If your hoist is unable to lift your boat out of the water, this means that your motor under load cannot hold the voltage needed.

Solution? Make sure there are no voltage drops in your electrical system. The reason this can happen is that your motor will start demanding more amps under load and volts begin to drop.

You can also calculate how far is the motor from your breaker and make sure you are using the right gauge wires to accommodate voltage traveling through. You can use the following chart for reference:

In any case, using a heavier gauge wire than you already have may be a solution to your problem. Inadequate voltage is the main reason why boat lift manufacturers will void warranties if you are using an extension cord or a generator.

Don’t forget that using a wire that is specifically designed for the marine environment and making sure it is UL/CSA Listed, will help you avoid wire problems in the future.

How much are you really lifting?

Did you calculate properly your boat weight in the first place? Did you include:

  • Your fuel weight?
  • Weight of the cradle (if applicable)?
  • All the extra things that you purchased?
  • Anything else that was added to the boat after purchase?

In this case, if you miscalculated your boat weight and got a lift that is too small of capacity, you will experience a voltage drop. Your hoist will not be able to lift your boat out of the water and in some cases, your GFCI will disconnect the circuit.

This means that amperage demand has risen above the full load rating of your lift. If it stays this way long enough, your voltage will drop and breakers will trip to prevent further damage.

Improperly installed or insufficiently greased equipment could also give you a problem with low voltage. This is due to the fact more unnecessary friction is created by moving parts, that are rubbing against each other and putting an extra load on your motor.

Low voltage is the usual problem behind your motor stopping and not being able to pick up your boat. In order to get your motor to work, you will need to check the following:

  • How far is your motor from the power source? The longer the wire, the more chance you will experience a voltage drop.
  • Is your motor size adequate? It needs to be able to pick up your load. 1hp motor is the most common size for the boat lifts (3/4 and 1.5 sizes are also available).
  • Is your lift rating matching your load? When sizing the boat lift, look for the weight of the boat and add EVERYTHING  that will be lifted along with it (including fuel, fresh and wastewater tanks, non-factory modifications, generators, skis, etc.)

** Note. The weight of the fuel is about 6-7 lbs. per gallon. Water weighs approximately 8 lbs. per gallon, multiply that number by a full tank (count all the tanks you have) and you will get your maximum weight. You can use the following guide to find the overall weight of your boat (external link).

Check your voltage at the motor while it is trying to lift your load and compare it to the voltage reading at the plug (while the motor is off). If the difference is more than 4%, you have a low voltage issue.

Your switch could be defective as well. If there is a difference in voltage amount at the input and output sides, check the connections or get a new switch.

Quick Summary

When your boat lift is starting fine but stops while trying to pick up the load, it is highly likely an undervoltage problem. Following are the common reasons for voltage loss:

  1. Inadequate size and gauge wire.
  2. Overloaded lift.
  3. Improperly installed lift.
  4. Insufficient greasing of equipment.
  5. Use of generator or wire extensions.
  6. Corrosion or bad connection issues at the switch.
  7. Corrosion or bad connection issues at the motor.
  8. Trying to operate 220/230 volts-wired motor with at 110/115 volts power supply service.
  9. Overusing and therefore, overheating the motor.

** Warning! Undervoltage is a fire hazard!

Case #4. Your motor is damaged

When you hear a “grinding” sound as you turn the power ON, it’s most likely to be coming from the inside of your motor. This noise is coming from your motor’s bearings and if they are damaged in any way during shipping, your motor will run, but be excessively noisy.

If your motor gets very noisy with time, this could be due to the incorrect installation and improper enclosure. Any kind of water or moisture penetration will damage your motor over time.

Your motor could be also overused if you don’t give it enough breaks between lifts. If your motor was working fine and all of a sudden you see smoke coming out of it, it means that your copper windings are burning due to the excessive amount of amps coming through.

Some motors are completely sealed and only allow 15 minutes of runtime (or start and stop). If you don’t let it rest and cool down in between cycles for at least 5 minutes, it will overheat.

Once overheated, your motor is damaged and will require replacement. Some other reasons for overheated motor include (but are not limited to):

  1. Improper wiring.
  2. Overloading the motor.
  3. The inadequate voltage supply.
  4. The excessive voltage coming through.
  5. Running motor continuously without giving it time to rest (check manufacturer’s specifications).
  6. Constantly turning the motor ON and OFF, which could be easily done with remote control.
  7. Your motor is wired for the wrong service (220-230 volts instead of 110-115 volts, for example).

An overheated motor will have smog coming out of it and smell like it is burning.

** Warning! Before doing any electrical work, always disconnect the power source. If you are not a licensed electrician, DO NOT do any troubleshooting yourself!

Here are some boat lift safety instructions for you:

This is a user manual from BH-USA, where I got most of this information from. They seem to be very professional and knowledgeable about what they do.

Here are some boat repair services for you:

Attention! This article is for informational purposes ONLY and is NOT a replacement for professional advice! ALWAYS consult your local specialist for an appropriate solution to your problem. All statements, prices, contact information, recommendations, and reviews contained herein came from sources that we believe to be reliable, but the accuracy or completeness thereof is not guaranteed. Please contact the service provider for complete details and updates.

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