Replacing A Boat Starter: A Step-By-Step Guide For Beginners

Replacing a boat starter can be a challenging task, especially if the starter is located in a hard-to-reach place. The process typically involves disconnecting the electrical system, dismantling the old starter motor, and installing a new one. While it is possible to replace a boat starter yourself, it is important to prioritise safety and ensure that the mass switch and/or battery cable is disconnected before beginning any work. The cost of replacing a boat starter can vary depending on the type of engine and the accessibility of the starter, with inboard engine starters ranging from $40 to over $1,000 and outboard starters ranging from $100 to $500.

Disconnect the electrical system and battery

Disconnecting the electrical system and battery is the first step in replacing a boat starter. This is a crucial step to ensure safety during the replacement process. Here is a detailed guide on how to do it:

First, locate the battery and the mass switch or battery cable. The battery is typically located near the crankshaft, on the side of the flywheel housing. Once located, proceed to disconnect the battery cable from the battery. This will cut off the power supply to the starter motor. Make sure to also disconnect the mass switch if your boat has one.

Next, you need to identify the starter relay. This is usually controlled by a smaller cable (terminals S or 50) and is connected to the starter motor. Disconnect this cable as well. In some cases, the starter motor may be "mass-free," meaning the entire installation is free of mass, often the engine block. If this is the case, ensure that all cables connected to the starter motor are disconnected.

Mark the cables clearly to avoid confusion during the reassembly process. Also, check that the cables are not live by using a voltage tester to ensure that the electrical system is completely disconnected.

Now that the electrical system and battery are disconnected, you can proceed to the next step of removing the old starter motor. This process may vary depending on the make and model of your boat engine, so it is essential to refer to your boat's manual or seek guidance from a marine technician if you are unsure.

Remember to prioritize safety at all times when working on your boat's electrical system and starter motor.

Disassemble the starter motor

To replace a boat starter, you will need to disassemble the starter motor. This process can be challenging, especially if the starter is located in a hard-to-reach area. Here is a step-by-step guide to help you through the process:

Disconnect the electrical system: Before beginning any work on the starter motor, it is crucial to ensure that the electrical system is disconnected. Disconnect the battery or mass switch and verify that the cables are not live. In conventional starter motors, a thick cable runs directly from the positive battery terminal to the incoming copper bolt on the starter relay (Terminal B or 30). This is often the distribution point for the rest of the electrical system, so there may be multiple cables to keep track of. Mark them clearly to avoid confusion during reassembly.

Disconnect the starter relay: The starter relay is controlled by a smaller cable (terminals S or 50). Disconnect this cable. Some starter motors are "mass-free," meaning the entire installation is free of mass, often the engine block. In such cases, additional cables will need to be disconnected.

Remove the starter motor: With the electrical system disconnected, you can now remove the starter motor from the engine. This step may require some creativity with your tools, as accessibility is often limited, especially in tight engine spaces. The starter motor is typically attached to the flywheel housing with 2 or 3 bolts. Use a socket wrench and extensions as needed to reach the bolts. Be careful not to drop the starter motor into the bilge when removing the last bolt.

Inspect the components: Once the starter motor is removed, take the opportunity to inspect the components. Check the condition of the gears, the spring, the solenoid, and the electrical connections. Look for any signs of physical damage, corrosion, or wear. If the starter motor failed due to a specific issue, you may be able to identify the cause by examining these components.

Clean and prepare the surfaces: Before installing a new starter motor, ensure that all surfaces are clean and free of corrosion. Grease the material after installation to create a protective layer against moisture penetration. Use contact spray or conductive paste for proper protection between the contacts.

Reassembly: When you are ready to install the new starter motor, follow the disassembly steps in reverse. Ensure that the new starter motor is securely attached to the flywheel housing with the correct number of bolts. Reconnect the electrical cables, ensuring they are attached to the correct terminals.

Remember to exercise caution and patience throughout the process, especially when working in tight spaces. It may be helpful to take pictures or make notes during disassembly to aid in reassembly. If you encounter any complications or are unsure about any steps, consult a professional marine technician for assistance.

Find the right starter motor

Finding the right starter motor for your boat engine is a crucial step in the replacement process. Here are some detailed instructions and tips to help you with this task:

Step 1: Identify the Starter Motor Number

The easiest way to find the correct starter motor is by its number. This number is often printed on a label or engraved on the housing of the starter motor. You can use this number to search for the specific starter motor that fits your boat engine.

Step 2: Search by Make and Model

If you are unable to locate the starter motor number, you can also search for the make and model of your boat engine in the "starter motors" category on websites that sell marine parts. This method may require a bit more browsing, but it will help you find the right starter motor for your specific engine.

Step 3: Check the Dimensions and Specifications

When searching for a starter motor, pay close attention to the dimensions and specifications provided in the product descriptions. The most critical criteria are dimensions A and B, as these will ensure a proper fit for your engine.

Step 4: Consider the Rotation Type

Starter motors come in different rotation types, which are generally indicated at the front of the motor. Common types include CCW (Counter Clockwise), DD (Direct Drive), and GR (Gear Reduction). Make sure to select a starter motor with the correct rotation type for your engine.

Step 5: Compare Prices and Suppliers

Once you have identified the correct starter motor, take the time to compare prices from different suppliers. You can search for the part number or engine model to find the best deal. Additionally, consider the reputation and reliability of the supplier to ensure you are getting a quality product.

Step 6: Seek Professional Advice

If you are unsure or need further assistance, don't hesitate to consult a marine technician or a professional boat parts supplier. They can provide valuable guidance and ensure you find the right starter motor for your boat engine.

Remember, safety should always be a priority when working on boat engines. Make sure to disconnect the electrical system and battery before beginning any replacement or maintenance work.

Install the new starter

Installing a new starter motor is a simple process, but it does require attention to detail and some physical contortion to reach the right spots!

Firstly, make sure all surfaces are clean and free of corrosion. You should also ensure that the mass switch and/or battery cable is disconnected. The starter motor is usually located near the crankshaft, on the side of the flywheel housing.

Now, you can begin to install the new starter. This is done in reverse order to the removal process. The new starter needs to be held in place as the mounting screws are inserted. This can be tricky, as you may need to get both hands into a tight space and feel around for the right spots.

Once the new starter is in place, you should grease the material. This acts as a protective layer against moisture. For proper protection between the contacts, use contact spray or conductive paste.

Check for proper functioning

Once you have replaced your boat starter, you will want to check that it is functioning properly. Here are some ways to do that:

Check the Connections

First, check the connections between the starter and the battery. Ensure that all connections are tight and free of corrosion. If you notice any corrosion, clean it off with a wire brush and reconnect the cables.

Check the Battery Voltage

Use a multimeter to test the voltage of your battery. If the voltage is low, it may need to be replaced or recharged. Set the multimeter in DC to 20V and check the voltage; it should read around 12 volts or more. If it is lower than that, your battery may need to be recharged or replaced.

Check for Unusual Noises

If you hear a clicking noise when trying to start your boat engine, it could be an indication that your starter is not functioning properly. This noise is caused by the starter solenoid trying to engage the starter motor but failing to do so. Another sign of a faulty starter is a grinding noise, which is caused by the starter gear not properly engaging with the flywheel. Address any issues with unusual noises as soon as possible to avoid further damage to your engine.

Check the Starter Itself

Visually inspect the starter for any signs of damage or wear. If you notice any damage, the starter may need to be replaced. You can also test the starter using a voltmeter. Connect the voltmeter to the starter and have someone turn the key in the ignition. If the voltmeter reads 12 volts or more, the starter is receiving power, and the issue may lie elsewhere. If the voltmeter reads less than 12 volts, the starter may not be receiving enough power and may need to be replaced.

Frequently asked questions