Save Money and Time with These Starter Repair Tips and Tricks

A starter is a crucial component of any diesel engine generator as it helps to start the engine. However, starters can sometimes experience problems and stop working, leading to frustration and downtime for the generator. While it may be tempting to replace the starter, this can be an expensive and time-consuming solution. Instead, you can take steps to troubleshoot and repair your starter without having to replace it entirely. 

In this guide, we'll cover the most common problems that diesel engine generators experience with their starters and provide step-by-step instructions on how to fix them. Whether you're an experienced mechanic or a beginner, this guide will provide the information you need to get your generator up and running again quickly and efficiently.

How does a starter motor work? 

The basic function of the starter motor is to turn the engine over, which creates compression and allows the fuel-air mixture to ignite, starting the engine. The starter motor typically consists of an electric motor, a solenoid, and a drive gear.

When the key is turned, electrical power is sent from the battery to the solenoid. The solenoid then energizes the electric motor, which rotates the drive gear. The drive gear is attached to the end of the starter motor and engages with the engine's flywheel. When the drive gear turns, it turns the flywheel and cranks the engine, causing it to start.

The electric motor is powered by the battery and uses its rotational energy to turn the engine over. The solenoid is responsible for transmitting electrical power from the battery to the starter motor. If the battery is weak or the solenoid is damaged, the starter motor may not receive enough power to turn over the engine, resulting in a no-start condition.

The Bendix drive is another crucial part of the starter motor. A device called the Bendix drive connects the flywheel and starter gear. When the engine runs, the Bendix drive, a spring-loaded gear, generally disengages from the flywheel. The solenoid activates the electric motor when the ignition key is turned, turning the Bendix drive. The flywheel and starter gear are then engaged by the Bendix drive, starting the engine. The Bendix drive disengages from the flywheel and returns to its regular position once the engine fires up.

Starter Motor Components 

A starter motor consists of several key components that combine to turn the engine over and initiate the combustion process. Read here How to identify Generator starter motor problems and solutions.

Gear System Of The Starter Motor 

The gear system of the starter motor in a diesel generator is a critical component that allows the motor to transfer its rotational force to the engine and initiate its combustion process. The gear system consists of several key components that work together to ensure that the starter motor can effectively start the engine.

1. Drive Gear: The part that attaches the starter motor to the engine is the driving gear. Normally, it is found at the armature's tip. It is made to mesh with the engine's flywheel, transferring the rotational force produced by the starter motor to the engine.

2. Pinion Gear: A small gear called the pinion gear is affixed to the driving gear and is in charge of meshing with the engine's ring gear. It is often found at the end of the driving gear and is made to revolve around the armature's axis.

3. Ring Gear: The ring gear is a component mounted outside the engine's flywheel. It is responsible for receiving the rotational force generated by the pinion gear and transmitting it to the engine's crankshaft, initiating the combustion process.

4. Clutch: The clutch is a component that allows the drive gear to be disengaged from the ring gear once the engine has started. It prevents the starter motor from continuing to turn the engine once it is running, and it also helps to protect the starter motor from damage caused by the engine's high torque.

5. Bendix Drive: The Bendix drive is a component that automatically engages and disengages the drive gear and pinion gear as the starter motor rotates. It is designed to ensure that the drive and pinion gear are always properly aligned, even when the engine is difficult to start.

The gear system of the starter motor in a diesel engine generator is a complex and highly engineered component that must function correctly to ensure that the engine starts quickly and reliably. By providing a direct mechanical connection between the starter motor and the engine, the gear system allows the starter motor to transfer its rotational force to the engine, initiating the combustion process and allowing the generator to provide power when needed.

Releasing The key 

When the key is released after starting a generator, several actions happen at the starter motor. The starter motor is a key component in starting the generator as it is responsible for turning the engine over and getting it to start.

Once the key is released, the starter motor stops cranking the engine, and the engine takes over and begins to run on its own. At this point, the starter motor is no longer needed, and the electrical circuit used to start the engine is disconnected. It is often done through an over-running clutch, which disengages the starter motor from the engine as soon as it begins to run.

The solenoid switch, an electrically operated switch that controls the flow of electrical current to the starter motor, is also de-energized. It stops the flow of current to the starter motor and prevents it from continuing to turn.

 How might a starter motor be repaired rather than changed?

If you want to fix a starter motor without replacing it, you'll need to dismantle it and perform some maintenance and repairs. Here are the steps you can follow:

1. Safety precautions: Before starting the repair work, wear safety glasses and gloves to protect your eyes and hands from debris and oil. Disconnect the battery terminals to avoid any electrical hazards.

2. Preparation: Place a clean cloth or towel underneath the starter motor to catch any parts that may fall off during disassembly. You may also want a parts tray or container to keep screws, nuts, and other small parts organized.

3. Removing the starter motor: Locate the bolts that hold the starter motor in place. Remove the bolts and any electrical connections, and gently lower the starter motor out of the engine.

4. Disassembling the starter motor: Carefully separate the starter motor into its components, such as the housing, armature, commutator, and brush assembly. You can refer to the manufacturer's manual for specific instructions on how to disassemble your particular starter motor.

5. Disassembling a Perkins starter motor requires a specific set of tools and a systematic approach. Here's a general guideline to help you disassemble a Perkins starter motor:

6. Prepare your tools: You will need a set of socket wrenches, pliers, and screwdrivers. A torque wrench is also useful but not necessary.

7. Remove the mounting bolts: The bolts holding the starter motor to the engine must first be removed. To remove the bolts, use a socket wrench.

8. Separate the solenoid and motor assembly: The solenoid and motor assembly are typically connected by a bracket. Remove the bolts that secure the bracket to the solenoid and motor, then separate the two components.

9. Remove the brush holder assembly: Locate the assembly, typically held in place by a retaining clip. Use pliers to remove the clip and lift the brush holder assembly out of the motor.

10. Remove the armature: The revolving component of the starter motor attached to the pinion gear is called the armature. Usually, a set of through bolts is used to secure it. To remove the bolts and lift the armature out of the motor, use a socket wrench.

11. Remove the pinion gear: The pinion gear is located at the end of the armature shaft. It's typically held in place by a set of locking tabs. Use pliers to bend the tabs and remove the gear from the armature shaft.

12. Cleaning the components: Clean the components with a clean cloth and a solution of baking soda and water. Rinse with clean water and dry the components thoroughly.

13. Inspecting the components: Check the components for any signs of damage or wear, such as cracks, chips, or burn marks. If any of the components are damaged, you may need to replace them.

14. Replacing the brushes: If the brushes are worn, remove them and install new ones. Brushes are the most common cause of starter motor failure, so it's important to replace them if they're worn.

15. Reassembling the starter motor: Reassembling the starter motor, following the reverse of the disassembly process. Make sure all components are properly aligned and tightened.

16. Testing the starter motor: After reassembling the starter motor, reconnect the battery and test it to ensure it's working properly. If it still doesn't work, you may seek professional help.

These steps should help you fix a starter motor without replacing it. However, if the problem is beyond repair, it may be more cost-effective in the long run to replace the starter motor rather than trying to fix it.

Note: Always refer to the manufacturer's instructions for details on disassembling your particular Perkins starter motor. If you're unsure about a step or don't have the right tools, it's best to seek assistance from a professional mechanic 

Wiring Contacts 

Wiring contacts are an essential component of a starter motor for a diesel generator. They are responsible for transmitting electrical energy from the battery to the solenoid, which activates the starter motor to start the engine.

The wiring contacts in a starter motor consist of two main components: the battery terminal and the solenoid terminal. The battery terminal is connected to the positive terminal, while the solenoid terminal is connected to the solenoid coil.

When the starter motor is activated, electrical energy flows from the battery to the solenoid coil, creating a magnetic field that moves the solenoid plunger. The plunger then engages the pinion gear, which turns the engine flywheel to start the engine.

It's important to ensure that the wiring contacts are securely connected and free from corrosion. A loose or corroded connection can result in a weak or intermittent electrical signal, preventing the starter motor from functioning correctly. If you notice any wear or corrosion on the wiring contacts, it's best to replace them to ensure reliable engine starting.

Starter solenoid contacts. 

The solenoid is responsible for transmitting electrical energy from the battery to the starter motor, which in turn starts the engine. The solenoid contacts are the electrical connections between the solenoid coil and the battery.

The starter solenoid contacts have two main components: the battery terminal and the solenoid terminal. The battery terminal is connected to the positive terminal, while the solenoid terminal is connected to the solenoid coil. When the starter motor is activated, electrical energy flows from the battery to the solenoid coil, creating a magnetic field that moves the solenoid plunger. The plunger then engages the pinion gear, which turns the engine flywheel to start the engine. 

Control module 

The control module manages the engine's systems and electrical components, also referred to as the engine control module (ECM). It is the engine's "brain" and regulates several processes, including fuel injection, ignition timing, and emissions control.

In terms of its relationship to the starter motor, the control module plays a crucial role in the starting process. When the ignition key is turned, the control module signals the starter motor to engage and turn the engine over. It also manages the voltage sent to the starter motor to ensure that it has enough power to turn the engine but not too much power that could cause damage.

Additionally, the control module monitors the engine's starting process to ensure that it starts within a certain time frame and that there are no problems with the starter motor or other components. If the control module detects any issues, it can trigger a "no start" condition and prevent the engine from starting.

The control module and the starter motor work together to start the engine. The control module manages the starting process and provides the power and signals to the starter motor to turn the engine over.

Starter Motor Brushes 

Starter motor brushes are a crucial component of the starting system of a diesel engine generator. They play a vital role in transmitting electrical power to the starter motor's armature, which spins the engine's flywheel to start the engine. The starter motor brushes are typically made of graphite or carbon and are housed in a brush holder inside the starter motor.

The main function of the starter motor brushes is to transfer electrical power from the battery to the starter motor's armature. As the armature rotates, the brushes make contact with the commutator, which is the rotating part of the armature. This contact results in an electrical current flowing from the battery to the armature, creating a magnetic field that rotates the starter motor.

Starter motor brushes wear out over time due to friction and exposure to high temperatures, which can cause them to become worn and no longer make contact with the commutator. When this occurs, the starter motor may not function correctly, and the engine may not start. It is important to regularly inspect and replace the starter motor brushes to ensure reliable starting performance.

How to replace a starter motor 

Replacing a starter motor is a relatively simple task that can be performed with basic hand tools. The starter motor is responsible for turning over the engine to start the engine, and if it fails, the engine will not start. If you suspect your starter motor is failing, you can perform a simple test to determine if it needs to be replaced. If the starter motor does need to be replaced, the process typically involves removing the old starter motor and installing a new one in its place.

Get the required equipment and parts together before starting the replacement process. A replacement starter motor, pliers, wire nuts, and a socket set might be included. Additionally, because the procedure can change based on the make and model of the engine, it is crucial to refer to the owner's handbook of the car for detailed instructions on how to replace the starter motor.

Safety first

Safety is of utmost importance while removing the diesel generator starter motor for repair. Here are a few guidelines to ensure that the process is carried out safely:

1. Disconnect the power supply: Before starting any work, disconnect the generator's power supply to avoid electric shock.

2. Wear protective gear: Always wear protective gear such as gloves, safety glasses, and a hard hat to protect yourself from potential dangers.

3. Observe the manufacturer's guidelines: When removing the starter motor, carefully adhere to the manufacturer's instructions. It will make sure that you don't mutilate components or jeopardize the safety of the generator.

4. Use the right tools: Use the proper equipment to prevent damaging components or hurting yourself.

5. Work collaboratively: To aid with lifting and to handle large components and to provide an extra set of eyes to ensure that everything is done safely, it is ideal for working with a partner if at all possible.

6. Be mindful of hot surfaces: Be aware of any hot surfaces, such as the engine, as these can cause burns.

7. Avoid loose clothing: Avoid wearing loose clothing or jewelry that could get caught in moving parts.

8. Keep the work area clean: Keep the work area clean and free of clutter to avoid tripping hazards.

Remove the wiring 

To remove the starter motor; of a diesel generator, the first step is to remove the wiring connected to the starter motor. It involves disconnecting the battery cables from the battery and then disconnecting the wiring harness that connects the starter motor to the generator's electrical system.

It is important to ensure that the wiring is properly labeled and organized before removing it so that it can be easily reconnected when the starter motor is replaced.

Remove the starter and bolts 

After removing the wiring from the diesel generator's starter motor, the next step in removing the starter motor is to remove the motor itself, along with the bolts that hold it in place. These bolts are typically located on the back of the starter motor, where it attaches to the flywheel housing of the generator.

To remove; the starter motor, the bolts must first be loosened using a wrench or socket. Once the bolts are loose, the starter motor can be gently pulled away from the flywheel housing, being careful not to damage any surrounding components.

Once the starter motor has been removed, it should be inspected for any signs of damage or wear, such as broken or worn-out teeth on the gear or other parts. If any issues are found, the motor may need to be repaired or replaced before reinstalling. If no issues are found, the starter motor can be set aside, and the replacement process can begin.

Compare to verify 

When replacing a starter motor on a diesel generator, it is important to compare the new motor to the old one to ensure that they are the same. This process, known as "compare to verify," involves examining the physical characteristics of the two motors, such as their size, shape, and connections, to make sure that they match.

One way to compare the two motors is to take detailed measurements of each component, including the mounting bolts, shaft length and diameter, and electrical connections. These measurements can be used to confirm that the new motor is a perfect match for the old one.

Another method is to visually inspect the two motors side by side, looking for any noticeable differences in appearance or construction. Any variations between the two motors could indicate that they are not the same model and could lead to compatibility issues when installing the new motor.

Ultimately, taking the time to compare the old and new starter motors carefully can help ensure that the replacement process goes smoothly and that the generator continues to operate reliably.

Transfer heat shield 

A heat shield is a starter motor component designed to protect the motor from excess heat generated by the engine. It is usually made of metal or other heat-resistant materials and is positioned between the starter motor and the engine block.

If a starter motor has a heat shield, it is important to transfer it to the replacement motor during the installation process. The shield is crucial in preventing the motor from overheating and potentially failing.

To transfer; the heat shield, the first step is to remove the old motor from the engine. Once the motor is detached, the shield can be carefully removed by unbolting it from the motor. The shield should be inspected for any signs of damage, such as cracks or warping, and replaced if necessary.

Next, the shield should be cleaned to remove any dirt or debris that may have accumulated. Once the shield is clean and free of damage, it can be installed on the new starter motor by bolting it in place.

Replace with new starter 

Install the new starter motor: Align the new starter motor with the engine and insert any bolts or screws that are used to secure the motor in place. Reconnect the electrical connections to the new motor, making sure that each wire is connected to the correct terminal.

Reconnect the battery: Once the new motor is installed and all connections are secure, reconnect the battery to the generator.

Test the replacement starter motor: Start the generator and check that the replacement starter motor is working properly. Visually check the motor to make sure it is not overheating or releasing smoke, and listen for any unusual noises or vibrations that would signal a problem.

You can make sure the new starter motor is put in correctly and will give your diesel generator dependable operation by following these instructions.