Imagine your beautiful green lawn, a symbol of summer relaxation and outdoor enjoyment. But then, disaster strikes – your lawnmower sputters, coughs, and refuses to start. You’ve checked the fuel, the spark plugs, even the air filter, and still nothing. The culprit might be hiding in a seemingly innocuous component: the ignition coil. This vital part, responsible for generating the high voltage needed to ignite the spark plugs, can fail silently, leaving your lawnmower stranded. Thankfully, diagnosing a faulty coil is within your grasp – all you need is a simple ohmmeter and this comprehensive guide.
What is a Lawn Mower Coil and How Does it Work?
A lawnmower coil is a crucial component of the ignition system, acting as a transformer that increases the low voltage from the battery to a much higher voltage required to create a spark in the spark plugs. It essentially converts the battery’s 12-volt power into a powerful electrical surge, enabling the combustion process that powers your lawnmower.
H2: Why Use an Ohmmeter to Check Your Lawn Mower Coil?
An ohmmeter, a handy tool for measuring electrical resistance, becomes your best friend when diagnosing a faulty lawnmower coil. By testing the coil’s resistance, you can determine if it’s within the manufacturer’s specified range, indicating a healthy coil, or outside the acceptable limits, signaling a problem.
H2: Understanding Ohmmeter Readings
Before you delve into testing, let’s unravel the secrets of ohmmeter readings.
H3: What are Ohms?
Ohms, represented by the Greek letter Omega (Ω), are the units of measurement for electrical resistance. A high ohm reading signifies a greater resistance to electrical flow, while a low ohm reading implies less resistance.
H3: Ohmmeter Components
An ohmmeter typically features:
- Test Leads: These flexible wires with probes at their ends connect the ohmmeter to the component being tested.
- Dial or Digital Display: This displays the resistance reading in ohms.
- Selector Switch: Allows you to choose the appropriate measurement range for your test.
H2: Gathering Your Supplies
Before you start testing, make sure you have these essential items at hand:
- Ohmmeter: A digital multimeter with an ohmmeter function is ideal.
- Lawn Mower Manual: This provides the specific resistance specifications for your lawnmower coil.
- Safety Glasses: Protect your eyes from potential sparks.
- Gloves: Keep your hands safe when working with electrical components.
H2: Disconnecting the Coil
Safety comes first. Before you start testing, disconnect the coil from the rest of the lawnmower’s electrical system.
H3: Locate the Ignition Coil
The coil is typically located near the engine, often mounted on the engine block or near the spark plug wires. Consult your lawnmower manual for precise location details.
H3: Disconnect the Wires
Carefully disconnect the wires connected to the coil. These wires usually include the spark plug wire and the wire from the ignition switch.
H2: Testing the Ignition Coil
Now that the coil is disconnected, you’re ready to test it with your ohmmeter.
H3: Setting the Ohmmeter
Set your ohmmeter to the appropriate resistance range. The manual should specify the expected resistance values for your specific coil.
H3: Testing the Primary Winding
The primary winding is the thicker, shorter coil of wire inside the ignition coil. To test it, connect the ohmmeter’s test leads to the primary winding terminals. These terminals are usually marked “P” or “PR” on the coil. Note the reading displayed on the ohmmeter.
H3: Testing the Secondary Winding
The secondary winding is the thinner, longer coil of wire within the ignition coil. To test it, connect the ohmmeter leads to the secondary winding terminals, often labeled “S” or “SEC.” Record the reading on the ohmmeter.
H2: Interpreting the Results
After testing both primary and secondary windings, compare your readings to the specifications provided in your lawnmower manual.
H3: Within the Acceptable Range
If the ohmmeter readings fall within the manufacturer’s specified range for both primary and secondary windings, your ignition coil is likely in good working order.
H3: Outside the Acceptable Range
If the ohmmeter readings are significantly higher or lower than the specified range, your ignition coil might be faulty.
H4: High Resistance
A high ohm reading suggests a broken wire or a build-up of carbon inside the coil.
H4: Low Resistance
A low ohm reading might indicate a short circuit within the coil.
H2: Troubleshooting and Repair
If your ohmmeter readings indicate a faulty coil, you’ll need to address the problem.
H3: Replace the Coil
In most cases, replacing a faulty ignition coil is the most practical solution. Locate a compatible coil from your lawnmower’s manufacturer or a reputable parts supplier.
H3: Cleaning the Coil
If the problem is carbon buildup, carefully cleaning the coil terminals and contacts with a wire brush might resolve the issue.
H2: Safety Precautions
When working with electrical components, always prioritize safety:
- Disconnect Power: Ensure the lawnmower’s battery is disconnected before working on the ignition system.
- Avoid Metal Objects: Keep metal tools or jewelry away from electrical components to prevent short circuits.
- Wear Protective Gear: Use safety glasses and gloves to protect your eyes and hands.
- Seek Professional Assistance: If you’re unsure about any aspect of the process or encounter any difficulties, consult a qualified mechanic.
H2: Conclusion
Checking your lawnmower coil with an ohmmeter is a simple yet effective way to troubleshoot ignition issues. Armed with this guide and the right tools, you can diagnose a faulty coil, replace it if necessary, and get your lawnmower back in action. Remember, a healthy ignition coil is essential for a smooth-running lawnmower, so don’t let a faulty coil hold you back from enjoying your green oasis.
FAQs
What is a lawn mower coil?
A lawn mower coil is an essential component of the ignition system that transforms low voltage from the battery into a high voltage spark that ignites the fuel-air mixture in the combustion chamber. It consists of a primary winding and a secondary winding, wrapped around a metal core. When the ignition switch is turned on, current flows through the primary winding, creating a magnetic field. When the points or electronic ignition system breaks the primary circuit, the magnetic field collapses rapidly, inducing a high voltage in the secondary winding that creates the spark.
Understanding the function of the lawn mower coil is crucial when troubleshooting ignition issues as a faulty coil can prevent the engine from starting or running smoothly.
Why should I check the lawn mower coil with an ohmmeter?
Checking the lawn mower coil with an ohmmeter is essential for diagnosing ignition problems. A faulty coil can prevent the engine from starting or running properly. By measuring the resistance across the primary and secondary windings, you can determine if the coil is within the manufacturer’s specifications. If the resistance readings are out of range, it indicates that the coil is damaged and needs to be replaced.
This simple test can save you time and money by identifying the problem before replacing other parts unnecessarily.
What type of ohmmeter should I use?
A digital multimeter is recommended for checking a lawn mower coil. It offers more accurate and reliable readings compared to analog meters. Ensure that the multimeter has a range suitable for measuring the resistance values of both the primary and secondary windings of the coil. A range of 200 ohms for the primary winding and 20k ohms for the secondary winding should be sufficient.
Using an appropriate multimeter with the right range is crucial for obtaining accurate readings and diagnosing the coil effectively.
How do I connect the ohmmeter to the coil?
To connect the ohmmeter to the coil, first, identify the terminals on the coil. They are typically labeled with letters like “P” for primary and “S” for secondary, or they might have different colors, with black usually being the ground terminal. Connect the red lead of the ohmmeter to the terminal corresponding to the primary winding, and the black lead to the ground terminal. Then, repeat the process for the secondary winding, connecting the red lead to the terminal for the secondary winding and the black lead to the ground terminal.
Accurate connection of the ohmmeter leads to the correct terminals on the coil is critical for obtaining reliable resistance readings.
What are the normal resistance readings for a lawn mower coil?
The normal resistance readings for a lawn mower coil vary depending on the specific model and manufacturer. However, a typical range is 0.5-1.5 ohms for the primary winding and 10k-20k ohms for the secondary winding. These values are usually indicated in the owner’s manual or on a sticker attached to the coil itself.
Comparing the obtained readings to the manufacturer’s specifications will determine if the coil is working within its normal operating range.
What should I do if the resistance readings are out of range?
If the resistance readings for the primary or secondary winding are significantly out of range, it indicates that the coil is damaged and needs to be replaced. A faulty coil will prevent the engine from producing a spark, leading to starting and performance issues. However, before replacing the coil, ensure that the connections to the coil are secure and free from corrosion.
Replacing a faulty coil with a new one will restore the engine’s ability to produce a spark and ensure smooth operation.
What are some other reasons why my lawn mower won’t start?
Besides a faulty coil, there are several other reasons why your lawn mower might not start. These include a dead battery, dirty or corroded spark plugs, a faulty ignition switch, or clogged fuel lines. It’s always a good idea to perform a thorough inspection of the entire ignition system and fuel system to identify any other potential issues.
Addressing all potential causes of the starting problem will increase the chances of successfully troubleshooting and repairing the lawn mower.