Kohler Engine Coil Problem Fixes (5 Pro Tips For Woodcutters)

Aha! The unmistakable sputter, the frustrating pull after pull on the starter cord, the sinking feeling that your wood-splitting day is about to be cut short. I’ve been there, staring down a stubborn Kohler engine on my wood splitter, knowing that a faulty ignition coil could be the culprit. It’s happened enough times that I’ve developed a system, a troubleshooting routine that saves me time, money, and a whole lot of frustration. This article isn’t just about “Kohler engine coil problem fixes”; it’s about sharing the hard-earned knowledge that will keep your wood processing equipment running smoothly, so you can focus on the satisfying work of turning logs into warmth.

Kohler Engine Coil Problem Fixes: 5 Pro Tips for Woodcutters

The ignition coil is the heart of your engine’s ignition system. It takes the low-voltage electricity from the battery (or magneto system in some cases) and transforms it into the high-voltage spark needed to ignite the fuel-air mixture in the cylinder. When it fails, your engine won’t start or will run poorly. In the world of woodcutting and firewood preparation, where reliable equipment is essential, understanding how to diagnose and fix coil problems is a valuable skill.

Why This Matters to Woodcutters

Imagine this: You’ve spent the morning felling trees, bucking them into manageable lengths. The hydraulic log splitter is humming, turning those rounds into perfectly sized pieces of firewood. The sun is setting, and you’re almost finished, picturing a cozy evening by the fire. Then, cough, sputter, silence. The engine dies.

That’s when you realize a faulty ignition coil can halt an entire operation. Whether you’re a hobbyist preparing firewood for your home or a small-scale logging business relying on your equipment for income, downtime is costly. This guide will equip you with the knowledge to troubleshoot, diagnose, and potentially fix coil issues yourself, saving you time and money.

Key Terms and Concepts

Before diving into the fixes, let’s clarify some key terms:

Ignition Coil: The component that steps up the voltage to create a spark at the spark plug.
Spark Plug: The device that ignites the fuel-air mixture in the engine cylinder.
Magneto: A type of electrical generator that produces the current for the ignition system. Commonly found in small engines like those on chainsaws and wood splitters.
Air Gap: The small distance between the ignition coil and the flywheel magnets. This gap is crucial for proper coil function.
Flywheel: A rotating mechanical device that stores rotational energy. It also houses the magnets that interact with the ignition coil.
Ohmmeter/Multimeter: An electrical instrument used to measure resistance, voltage, and current. Essential for diagnosing electrical problems.
Green Wood: Freshly cut wood with high moisture content.
Seasoned Wood: Wood that has been dried to reduce its moisture content, making it ideal for burning. Typically, seasoned wood has a moisture content of 20% or less.
Felling: The process of cutting down a tree.
Bucking: Cutting a felled tree into shorter lengths.
Splitting: Dividing logs into smaller pieces, typically for firewood.

Pro Tip 1: The Initial Inspection – Visual Clues and Basic Checks

The first step in diagnosing any engine problem, especially a potential coil issue, is a thorough visual inspection. This often reveals obvious problems that can be easily addressed.

Step-by-Step Guide: Visual Inspection

Safety First: Disconnect the spark plug wire from the spark plug. This prevents accidental starting during the inspection.
Coil Body Inspection: Carefully examine the coil for any visible signs of damage. Look for:
- Cracks: Cracks in the coil housing can allow moisture to penetrate, leading to short circuits.
- Swelling: A swollen coil often indicates internal damage due to overheating or electrical overload.
- Burn Marks: Burn marks are a clear sign of electrical arcing or short circuits.
- Corrosion: Corrosion on the coil terminals or body can impede electrical conductivity.
Wiring Inspection: Check the wiring connected to the coil for:
- Loose Connections: Ensure all wires are securely attached to the coil terminals.
- Damaged Insulation: Look for cuts, abrasions, or cracks in the wire insulation. Exposed wires can cause short circuits.
- Corrosion: Check for corrosion on the wire terminals and connectors.
Spark Plug Wire Inspection: Inspect the spark plug wire for:
- Cracks or Cuts: Damage to the spark plug wire can cause spark leakage.
- Secure Connection: Ensure the wire is securely attached to both the coil and the spark plug.
Cleanliness: Clean the coil and surrounding area with a brush or cloth to remove any dirt, debris, or oil. This can help improve electrical conductivity and prevent overheating.

Strategic Insights

Early Detection: Regular visual inspections can help identify potential problems before they lead to complete coil failure.
Environmental Factors: Consider the operating environment. Coils on equipment used in damp or dusty conditions are more prone to corrosion and damage.
Record Keeping: Keep a log of inspections and any repairs performed. This can help you track the performance of your equipment and identify recurring issues.

Case Study: The Cracked Coil

I once had a wood splitter that was consistently hard to start. After several frustrating attempts, I decided to perform a thorough visual inspection. I discovered a hairline crack on the underside of the ignition coil. While the crack was barely visible, it was enough to allow moisture to penetrate the coil, causing intermittent starting problems. Replacing the coil solved the issue immediately.

Tool Specifications

Flashlight: Essential for inspecting hard-to-reach areas.
Wire Brush: For cleaning corrosion from terminals.
Cloth: For wiping down the coil and surrounding area.

Pro Tip 2: The Air Gap – Setting It Right for Optimal Performance

The air gap is the distance between the ignition coil and the flywheel magnets. This gap is crucial for proper coil function. If the gap is too large, the magnetic field will be too weak to induce sufficient voltage in the coil. If the gap is too small, the coil can rub against the flywheel, causing damage.

Step-by-Step Guide: Setting the Air Gap

Locate the Air Gap: The air gap is typically located between the coil’s core and the flywheel magnets.
Loosen the Coil Mounting Bolts: Slightly loosen the bolts that secure the coil to the engine block. This will allow you to adjust the position of the coil.
Use a Feeler Gauge or Business Card: The recommended air gap is typically between 0.010 and 0.014 inches (0.25 to 0.35 mm). A business card or a specific feeler gauge of the correct thickness can be used as a spacer.
Position the Spacer: Place the spacer between the coil core and the flywheel magnets.
Tighten the Mounting Bolts: Gently tighten the coil mounting bolts while ensuring the spacer remains in place.
Remove the Spacer: Once the bolts are tightened, remove the spacer.
Verify the Gap: Rotate the flywheel by hand to ensure there is no rubbing or contact between the coil and the flywheel.

Strategic Insights

Manufacturer Specifications: Always consult the engine manufacturer’s specifications for the correct air gap. This information can usually be found in the engine’s owner’s manual or on the manufacturer’s website.
Impact of Incorrect Gap: An incorrect air gap can lead to:
- Hard Starting: Difficulty starting the engine.
- Weak Spark: A weak spark can result in poor engine performance.
- Coil Damage: Contact between the coil and the flywheel can damage the coil.
Regular Checks: Periodically check the air gap to ensure it remains within the specified range.

Case Study: The No-Start Nightmare

I spent hours troubleshooting a wood chipper that refused to start. I checked the spark plug, fuel lines, and even the carburetor. Finally, I decided to check the air gap. To my surprise, the gap was significantly larger than the specified 0.012 inches. Someone had likely bumped the coil, shifting its position. After resetting the air gap, the chipper started on the first pull.

Tool Specifications

Feeler Gauge Set: A set of feeler gauges with various thicknesses.
Business Card: A standard business card can be used as a spacer.
Wrench or Socket Set: For loosening and tightening the coil mounting bolts.

Pro Tip 3: The Ohmmeter Test – Diagnosing Internal Coil Failure

An ohmmeter (or multimeter) is an invaluable tool for diagnosing electrical problems, including ignition coil failures. By measuring the resistance of the coil windings, you can determine if there are any internal shorts or open circuits.

Step-by-Step Guide: Ohmmeter Testing

Safety First: Disconnect the spark plug wire from the spark plug. Disconnect the coil from the engine wiring harness.
Set the Ohmmeter: Set the ohmmeter to the appropriate resistance range (typically in the ohms or kilohms range). Consult your ohmmeter’s manual for specific instructions.
Measure Primary Resistance: Connect the ohmmeter leads to the primary terminals of the coil (typically the small terminals). Record the resistance reading.
Measure Secondary Resistance: Connect one ohmmeter lead to the spark plug terminal and the other lead to one of the primary terminals. Record the resistance reading.
Compare to Specifications: Compare the measured resistance values to the manufacturer’s specifications. These specifications can usually be found in the engine’s service manual.

Interpreting the Results

Open Circuit (Infinite Resistance): An infinite resistance reading indicates an open circuit in the coil windings. This means the coil is not conducting electricity and needs to be replaced.
Short Circuit (Zero or Very Low Resistance): A zero or very low resistance reading indicates a short circuit in the coil windings. This means the coil is bypassing the normal electrical path and needs to be replaced.
Resistance Outside Specifications: If the measured resistance is significantly higher or lower than the manufacturer’s specifications, it indicates a problem with the coil. The coil may be partially damaged and should be replaced.
Acceptable Resistance: If the measured resistance is within the manufacturer’s specifications, the coil is likely functioning correctly. However, it’s still possible for a coil to fail under load, so further testing may be necessary.

Strategic Insights

Accurate Specifications: It is crucial to have the correct resistance specifications for your specific engine model. Using incorrect specifications can lead to misdiagnosis.
Temperature Sensitivity: Coil resistance can be affected by temperature. Perform the ohmmeter test at room temperature for the most accurate results.
Coil Condition: An ohmmeter test can only detect certain types of coil failures. It cannot detect intermittent problems or failures that only occur under load.

Case Study: The Intermittent Spark

I had a chainsaw that would start and run for a few minutes, then suddenly die. After letting it cool down, it would start again, only to repeat the cycle. I suspected a coil issue, but the visual inspection revealed nothing. An ohmmeter test showed that the coil’s secondary resistance was slightly outside the manufacturer’s specifications. Although the difference was small, it was enough to cause the intermittent spark problem. Replacing the coil resolved the issue.

Tool Specifications

Ohmmeter/Multimeter: A reliable ohmmeter with accurate resistance measurement capabilities.
Engine Service Manual: Provides the correct resistance specifications for your engine model.

Pro Tip 4: The Spark Test – Confirming Spark Delivery

Even if the coil appears to be functioning correctly based on visual inspection and ohmmeter testing, it’s essential to confirm that it is actually delivering a spark to the spark plug.

Step-by-Step Guide: Spark Testing

Safety First: Disconnect the spark plug from the engine.
Reconnect the Spark Plug Wire: Reattach the spark plug wire to the spark plug.
Ground the Spark Plug: Hold the spark plug against a clean, unpainted metal surface on the engine block. This provides a ground for the spark. Important: Ensure that the spark plug is held securely and that your hands are clear of the spark plug electrode.
Pull the Starter Cord: Pull the starter cord briskly while observing the spark plug electrode.
Observe the Spark: Look for a strong, consistent blue spark jumping across the spark plug gap.

Interpreting the Results

Strong Blue Spark: A strong, consistent blue spark indicates that the coil is functioning correctly and delivering adequate voltage to the spark plug.
Weak or Yellow Spark: A weak or yellow spark indicates that the coil is not delivering enough voltage. This can be caused by a faulty coil, a weak magneto, or a problem with the wiring.
No Spark: No spark indicates a complete failure of the ignition system. This can be caused by a faulty coil, a broken spark plug wire, or a problem with the magneto.

Alternative Spark Test Methods

Spark Tester: A spark tester is a specialized tool that makes it easier to observe the spark. It typically consists of a clip that attaches to the spark plug wire and a viewing window that allows you to see the spark.
In-Line Spark Tester: An in-line spark tester is installed between the spark plug wire and the spark plug. It allows you to monitor the spark while the engine is running.

Strategic Insights

Proper Grounding: Ensure that the spark plug is properly grounded to the engine block. A poor ground can prevent the spark from jumping across the gap.
Spark Plug Condition: A fouled or worn spark plug can affect the quality of the spark. Replace the spark plug if it is in poor condition.
Safety Precautions: Always exercise caution when performing a spark test. Avoid touching the spark plug electrode while the engine is being cranked.

Case Study: The Phantom Spark

I was working on a generator that would occasionally stall under load. The engine would start and run fine at idle, but it would die as soon as I plugged in an appliance. I performed a spark test and observed a weak, intermittent spark. The spark was present, but it was not strong enough to ignite the fuel-air mixture under load. Replacing the ignition coil solved the problem.

Tool Specifications

Spark Plug Wrench: For removing and installing the spark plug.
Spark Tester (Optional): A specialized tool for observing the spark.

Pro Tip 5: The Replacement – Choosing the Right Coil and Installation

If your testing indicates that the ignition coil is faulty, the next step is to replace it. Choosing the correct replacement coil and installing it properly are crucial for ensuring optimal engine performance.

Step-by-Step Guide: Coil Replacement

Identify the Correct Replacement Coil:
- Engine Model Number: The most reliable way to identify the correct replacement coil is to use the engine model number. This number is typically stamped on the engine block or on a label attached to the engine.
- Manufacturer’s Website: Visit the engine manufacturer’s website and enter the engine model number to find the correct replacement coil.
- Parts Catalogs: Consult parts catalogs from reputable aftermarket parts suppliers.
Gather Tools and Materials:
- Wrench or Socket Set: For removing and installing the coil mounting bolts.
- Screwdriver: For disconnecting and reconnecting wiring.
- Feeler Gauge or Business Card: For setting the air gap.
- New Ignition Coil: The correct replacement coil for your engine model.
Disconnect the Old Coil:
- Safety First: Disconnect the spark plug wire from the spark plug.
- Disconnect Wiring: Disconnect the wiring from the old coil.
- Remove Mounting Bolts: Remove the bolts that secure the old coil to the engine block.
Install the New Coil:
- Position the New Coil: Position the new coil in the same location as the old coil.
- Install Mounting Bolts: Install the mounting bolts and tighten them slightly.
- Set the Air Gap: Use a feeler gauge or business card to set the air gap between the coil and the flywheel magnets.
- Tighten Mounting Bolts: Tighten the mounting bolts securely.
- Reconnect Wiring: Reconnect the wiring to the new coil.
Test the Engine:
- Reconnect Spark Plug Wire: Reconnect the spark plug wire to the spark plug.
- Start the Engine: Start the engine and verify that it runs smoothly.

Strategic Insights

OEM vs. Aftermarket: You can choose between OEM (Original Equipment Manufacturer) coils and aftermarket coils. OEM coils are typically more expensive but are guaranteed to meet the engine manufacturer’s specifications. Aftermarket coils can be a more affordable option, but it’s essential to choose a reputable brand.
Coil Quality: The quality of the ignition coil can significantly impact engine performance and reliability. Invest in a high-quality coil from a reputable manufacturer.
Proper Installation: Proper installation is crucial for ensuring optimal coil performance. Follow the manufacturer’s instructions carefully and double-check all connections.

Case Study: The Wrong Coil

I once tried to save money by purchasing a generic aftermarket ignition coil for my log splitter. The coil fit and seemed to work initially, but the engine started running poorly after a few hours of use. I later discovered that the coil’s output voltage was not compatible with my engine, causing misfires and reduced performance. I learned the hard way that it’s always best to use the correct replacement coil for your specific engine model.

Tool Specifications

Wrench or Socket Set: For removing and installing the coil mounting bolts.
Screwdriver: For disconnecting and reconnecting wiring.
Feeler Gauge or Business Card: For setting the air gap.
Torque Wrench (Optional): For tightening the mounting bolts to the specified torque.

Additional Considerations for Woodcutters

Beyond the five pro tips, here are some additional factors to consider when dealing with ignition coil problems in woodcutting equipment:

Vibration: Chainsaws, log splitters, and other woodcutting equipment are subjected to significant vibration. This vibration can loosen connections, damage wiring, and cause coil failures. Regularly inspect your equipment for loose connections and damaged wiring.
Heat: Engines generate a lot of heat, which can damage ignition coils. Ensure that the coil is properly ventilated and protected from excessive heat.
Moisture: Moisture can cause corrosion and short circuits in ignition coils. Keep your equipment dry and protect it from the elements.
Fuel Type: Using the wrong type of fuel can damage the engine and potentially affect the ignition coil. Always use the fuel type recommended by the engine manufacturer.
Maintenance: Regular engine maintenance, including spark plug replacement and air filter cleaning, can help prevent coil failures.

Strategic Advantages of DIY Coil Repair

Cost Savings: Diagnosing and fixing coil problems yourself can save you significant money on repair costs.
Reduced Downtime: You can get your equipment back up and running quickly without having to wait for a repair shop.
Increased Knowledge: You’ll gain a better understanding of how your engine works and how to troubleshoot problems.
Self-Reliance: You’ll be able to handle minor repairs yourself, reducing your dependence on repair shops.

Next Steps: Implementing Your Knowledge

Now that you have a solid understanding of how to diagnose and fix Kohler engine coil problems, it’s time to put your knowledge into practice.

Inspect Your Equipment: Start by performing a thorough visual inspection of your woodcutting equipment. Look for any signs of damage, loose connections, or corrosion.
Gather Your Tools: Assemble the necessary tools, including an ohmmeter, feeler gauge, wrench set, and screwdriver.
Create a Maintenance Schedule: Develop a regular maintenance schedule for your equipment, including coil inspections, spark plug replacement, and air filter cleaning.
Consult the Manual: Always refer to the engine manufacturer’s service manual for specific instructions and specifications.
Practice and Learn: The more you work on your equipment, the more comfortable you’ll become with diagnosing and fixing problems.

By following these pro tips and implementing a proactive maintenance schedule, you can keep your woodcutting equipment running smoothly and efficiently, ensuring that you’re always ready to tackle your next wood processing or firewood preparation project. And remember, that satisfying warmth from a wood-burning fire is worth the effort!