How to Check Chainsaw Coils (5 Expert Tips for Accurate Testing)
“A chainsaw’s coil is like the heart of its ignition system. When it falters, the whole machine grinds to a halt. Knowing how to check it accurately can save you time, money, and a whole lot of frustration in the woods.” – Arborist and Chainsaw Repair Specialist, Mark Olsen
Understanding the Chainsaw Ignition System
Before diving into the testing process, it’s crucial to understand how the chainsaw ignition system works. The system typically consists of:
- Flywheel: A rotating component with magnets embedded in it.
- Ignition Coil: Generates the high-voltage spark.
- Spark Plug: Ignites the air-fuel mixture in the cylinder.
- Kill Switch: Grounds the ignition system to stop the engine.
As the flywheel rotates, the magnets pass by the ignition coil, inducing a voltage. This voltage is amplified by the coil and sent to the spark plug, creating a spark that ignites the fuel mixture. A properly functioning coil is essential for reliable engine operation.
Why Chainsaw Coils Fail
Chainsaw coils can fail for various reasons, including:
- Overheating: Prolonged use or inadequate cooling can cause the coil to overheat and break down.
- Vibration: Constant vibration can damage the coil’s internal components.
- Moisture: Exposure to moisture can cause corrosion and short circuits.
- Physical Damage: Impacts or mishandling can physically damage the coil.
- Age: Like any electronic component, coils can degrade over time.
5 Expert Tips for Accurate Chainsaw Coil Testing
Here are five expert tips to help you accurately test your chainsaw coil:
1. Visual Inspection: The First Line of Defense
Before you even grab a multimeter, start with a thorough visual inspection. Look for:
- Cracks or Breaks: Check the coil body for any visible cracks or breaks.
- Corrosion: Look for signs of corrosion on the coil terminals or wiring.
- Loose Connections: Ensure all wiring connections are secure and not frayed.
- Burn Marks: Check for burn marks or melted plastic, indicating overheating.
Personal Story: I once spent hours troubleshooting a chainsaw that wouldn’t start, only to discover a tiny crack in the coil body. It was barely visible, but it was enough to disrupt the electrical flow. A careful visual inspection would have saved me a lot of time and frustration.
2. Air Gap Measurement: Precision is Key
The air gap, the distance between the coil and the flywheel magnets, is crucial for proper coil function. Too large or too small, and the coil won’t generate enough voltage.
- Locate the Air Gap: Consult your chainsaw’s service manual to find the correct air gap specification (usually between 0.010 and 0.020 inches).
- Use a Feeler Gauge: Use a feeler gauge of the specified thickness to set the air gap. Loosen the coil mounting screws, insert the feeler gauge between the coil and flywheel magnets, and tighten the screws.
- Check Flywheel Condition: Make sure the flywheel magnets are clean and free of debris. Any rust or dirt can affect the magnetic field and impact coil performance.
Why This Matters: An incorrect air gap can cause weak spark, hard starting, or even no spark at all. Even a slight deviation from the recommended specification can make a big difference.
3. Resistance Testing: Unveiling Internal Flaws
Resistance testing measures the coil’s internal resistance using a multimeter. This can help identify short circuits or open circuits within the coil.
- Set Up Your Multimeter: Set your multimeter to the Ohms (Ω) setting.
- Primary Coil Resistance: Measure the resistance between the coil’s primary terminals (usually the terminals connected to the wiring harness). Consult your chainsaw’s service manual for the correct resistance range. A reading outside the specified range indicates a problem with the primary coil.
- Secondary Coil Resistance: Measure the resistance between the coil’s spark plug wire terminal and one of the primary terminals. Again, consult your service manual for the correct range. An open circuit (infinite resistance) or a very low resistance indicates a faulty secondary coil.
Data Point: According to my experience, the primary coil resistance typically falls between 0.5 and 3 ohms, while the secondary coil resistance ranges from 2,000 to 10,000 ohms. However, always refer to your chainsaw’s service manual for the exact specifications.
4. Spark Testing: Seeing is Believing
Spark testing verifies whether the coil is producing a strong spark.
- Remove the Spark Plug: Remove the spark plug from the cylinder.
- Connect the Spark Plug to the Coil: Reconnect the spark plug to the spark plug wire.
- Ground the Spark Plug: Hold the spark plug against a metal part of the engine (grounding it).
- Pull the Starter Rope: Pull the starter rope and observe the spark plug gap. You should see a strong, blue spark. A weak, yellow spark or no spark indicates a faulty coil.
Caution: Be careful when performing spark testing, as the high-voltage spark can be dangerous. Wear insulated gloves and avoid touching the spark plug wire while pulling the starter rope.
Alternative Method: You can use an inline spark tester, which connects between the spark plug and the spark plug wire. This allows you to observe the spark without removing the spark plug from the cylinder.
5. Voltage Testing: Measuring the Electrical Output
Voltage testing measures the voltage output of the coil while the engine is running or being cranked.
- Use a Peak Voltage Adapter: You’ll need a peak voltage adapter for your multimeter, which can capture the peak voltage generated by the coil.
- Connect the Adapter: Connect the peak voltage adapter to your multimeter and connect the adapter’s probes to the coil’s primary terminals.
- Pull the Starter Rope: Pull the starter rope and observe the voltage reading on the multimeter. Consult your chainsaw’s service manual for the minimum acceptable voltage. A reading below the minimum indicates a weak or faulty coil.
Why This is Important: Voltage testing provides a more precise measurement of coil performance than spark testing. It can reveal subtle issues that might not be apparent during a visual inspection or spark test.
Chainsaw Coil Replacement: When Testing Isn’t Enough
If your coil fails any of the tests mentioned above, it’s time to replace it. Replacing a chainsaw coil is a relatively straightforward process, but it’s essential to follow these steps:
- Disconnect the Spark Plug Wire: Disconnect the spark plug wire from the spark plug.
- Remove the Old Coil: Remove the coil cover and disconnect the wiring harness from the old coil. Loosen the coil mounting screws and remove the old coil.
- Install the New Coil: Install the new coil, ensuring the air gap is properly set. Connect the wiring harness and tighten the mounting screws.
- Reconnect the Spark Plug Wire: Reconnect the spark plug wire to the spark plug.
- Test the Chainsaw: Start the chainsaw and verify that it runs smoothly.
Cost Considerations: Chainsaw Maintenance and Repair
Now, let’s delve into the costs associated with chainsaw maintenance and repair, including coil replacement. As someone who has spent countless hours maintaining chainsaws, I can tell you that these costs can vary significantly depending on several factors:
- Chainsaw Model: The make and model of your chainsaw can influence the cost of parts and labor.
- Repair Shop vs. DIY: Repairing the chainsaw yourself can save on labor costs, but requires knowledge and tools.
- Location: Labor rates and parts prices can vary depending on your geographic location.
- Part Quality: Aftermarket parts are often cheaper than OEM (Original Equipment Manufacturer) parts, but may not be as reliable.
Chainsaw Coil Costs
The cost of a chainsaw coil can range from $15 to $100 or more, depending on the chainsaw model and the brand of the coil. OEM coils tend to be more expensive than aftermarket coils.
Data Point: I recently replaced the coil on my Stihl MS 271 chainsaw. The OEM coil cost me $75, while an aftermarket coil was available for around $30. I opted for the OEM coil, as I’ve had better experiences with their reliability.
Labor Costs
If you choose to have a professional repair your chainsaw, you’ll need to factor in labor costs. Chainsaw repair shops typically charge $50 to $100 per hour for labor. The cost of replacing a coil will depend on the complexity of the repair and the shop’s labor rate.
Example: If a repair shop charges $75 per hour and it takes them 1 hour to replace the coil, the labor cost would be $75. Adding the cost of the coil, the total repair cost could range from $90 to $175 or more.
Other Maintenance Costs
In addition to coil replacement, other chainsaw maintenance costs to consider include:
- Spark Plugs: $5 to $15 each
- Air Filters: $5 to $20 each
- Fuel Filters: $5 to $10 each
- Chainsaw Chains: $20 to $50 each
- Bar Oil: $10 to $20 per gallon
- Chain Sharpening: $10 to $20 per sharpening
Annual Maintenance Budget: I typically budget around $100 to $200 per year for chainsaw maintenance, depending on how frequently I use my chainsaws.
Firewood Preparation Costs
If you’re using your chainsaw to prepare firewood, you’ll also need to factor in the cost of firewood. Firewood prices can vary depending on the type of wood, the region, and the time of year.
Data Point: According to recent data, the average price of a cord of firewood in the United States ranges from $150 to $400, depending on the type of wood and the location. Hardwoods like oak and maple tend to be more expensive than softwoods like pine and fir.
Personal Experience: I live in a rural area where firewood is readily available. I typically purchase a cord of seasoned oak for around $250. However, I also harvest my own firewood from fallen trees on my property, which saves me money but requires more time and effort.
Firewood Processing Costs: If you’re processing your own firewood, you’ll need to factor in the cost of:
- Chainsaw Fuel: $5 to $10 per gallon
- Chainsaw Bar Oil: $10 to $20 per gallon
- Log Splitter Rental: $50 to $100 per day
- Labor (if hiring help): $15 to $30 per hour
Estimating Firewood Costs: To estimate the cost of preparing a cord of firewood, you can use the following formula:
Total Cost = (Wood Cost) + (Fuel Cost) + (Bar Oil Cost) + (Log Splitter Rental Cost) + (Labor Cost)
Example: Let’s say you purchase a cord of wood for $250, use 5 gallons of fuel at $7 per gallon, 1 gallon of bar oil at $15, rent a log splitter for $75 per day, and spend 10 hours processing the wood at $20 per hour. The total cost would be:
Total Cost = ($250) + (5 * $7) + ($15) + ($75) + (10 * $20) = $615
Therefore, the cost of preparing a cord of firewood in this example would be $615.
Cost Optimization Tips
Here are some tips for optimizing costs in wood processing and firewood preparation:
- Maintain Your Chainsaw: Regular maintenance, including sharpening the chain, cleaning the air filter, and replacing the spark plug, can extend the life of your chainsaw and prevent costly repairs.
- Shop Around for Parts: Compare prices from different suppliers before purchasing replacement parts. Aftermarket parts can be a good option if you’re on a budget, but be sure to read reviews and choose reputable brands.
- Consider Renting Equipment: If you only need a log splitter occasionally, renting one may be more cost-effective than purchasing one.
- Harvest Your Own Firewood: If you have access to fallen trees on your property, harvesting your own firewood can save you money. However, be sure to obtain any necessary permits and follow safety guidelines.
- Season Your Firewood: Seasoning firewood for at least six months before burning it can improve its efficiency and reduce emissions.
- Negotiate Prices: Don’t be afraid to negotiate prices with firewood suppliers or repair shops.
- Take Advantage of Sales: Look for sales on chainsaw parts, fuel, and bar oil.
- Learn to Sharpen Your Own Chains: Sharpening your own chains can save you money on sharpening services and improve your chainsaw’s performance.
Global Insights on Timber Prices and Fuelwood Markets
Timber prices and fuelwood market rates vary significantly across the globe. Factors such as timber species, quality, accessibility, and local demand influence these prices.
Europe: In Europe, timber prices are generally higher than in North America due to stricter environmental regulations and limited forest resources. Fuelwood is a popular heating source in many European countries, and demand has been increasing in recent years due to rising energy costs.
Asia: In Asia, timber prices vary widely depending on the country and the species. Some countries, such as Indonesia and Malaysia, have abundant timber resources, while others, such as Japan and South Korea, rely heavily on imports. Fuelwood is also a significant energy source in many Asian countries, particularly in rural areas.
Africa: In Africa, timber prices are generally lower than in other regions due to lower labor costs and less stringent environmental regulations. However, deforestation is a major concern in many African countries, and sustainable forestry practices are essential. Fuelwood is the primary energy source for many households in Africa, and demand is expected to continue growing as the population increases.
Data Source: The Food and Agriculture Organization of the United Nations (FAO) provides valuable data and reports on global timber prices and fuelwood markets.
Case Study: Budgeting for a Small-Scale Logging Operation
Let’s consider a case study of a small-scale logging operation in the Pacific Northwest region of the United States. The operation involves harvesting timber from a 10-acre plot of land.
Cost Components:
- Timber Purchase: $5,000 (based on timber appraisal)
- Logging Equipment Rental: $2,000 (chainsaws, skidders, loaders)
- Labor Costs: $8,000 (two-person logging crew for two weeks)
- Permits and Licenses: $1,000
- Fuel and Supplies: $500
- Transportation: $1,500 (hauling logs to the mill)
- Insurance: $500
Total Estimated Costs: $18,500
Revenue:
- Sale of Logs: $25,000 (based on market prices)
Profit:
- Total Profit: $6,500
Cost Management Strategies:
- Negotiate Timber Prices: Obtain multiple timber appraisals and negotiate the best possible price.
- Optimize Equipment Rental: Rent equipment for the shortest possible time to minimize rental costs.
- Control Labor Costs: Hire experienced and efficient logging crews to minimize labor hours.
- Minimize Fuel Consumption: Use fuel-efficient equipment and optimize logging operations to reduce fuel consumption.
- Explore Transportation Options: Compare transportation costs from different carriers and choose the most cost-effective option.
Calculations and Formulas
Here are some relevant calculations and formulas for wood processing and firewood preparation:
- Board Feet Calculation: To calculate the volume of logs in board feet, you can use the following formula:
Board Feet = (Length in Feet * Width in Inches * Thickness in Inches) / 12
- Cords Calculation: To calculate the volume of firewood in cords, you can use the following formula:
Cords = (Length in Feet * Width in Feet * Height in Feet) / 128
- Drying Time Estimation: To estimate the drying time of firewood, you can use the following rule of thumb:
Drying Time (Months) = (Moisture Content (%) - 20%) / 5
This formula assumes that firewood is properly stacked and exposed to adequate sunlight and airflow.
Actionable Takeaways
- Master Chainsaw Coil Testing: Learn the five expert tips for accurately testing chainsaw coils to diagnose ignition problems effectively.
- Budget Wisely: Develop a detailed budget for your wood processing or firewood preparation projects, considering all cost components.
- Optimize Costs: Implement cost optimization strategies to minimize expenses and maximize profits.
- Stay Informed: Stay up-to-date on timber prices, fuelwood market rates, and industry trends.
- Prioritize Safety: Always prioritize safety when working with chainsaws and other wood processing equipment.
Next Steps
- Review Your Chainsaw’s Service Manual: Consult your chainsaw’s service manual for specific instructions on coil testing and replacement.
- Practice Coil Testing: Practice the coil testing techniques outlined in this guide to become proficient in diagnosing ignition problems.
- Develop a Budget Template: Create a budget template for your wood processing or firewood preparation projects.
- Research Local Market Prices: Research local market prices for timber, firewood, and equipment rentals.
- Join a Woodworking Community: Connect with other woodworkers and share tips and experiences.
Conclusion
Checking chainsaw coils accurately is a valuable skill for anyone who relies on chainsaws for wood processing or firewood preparation. By following the five expert tips outlined in this guide, you can diagnose ignition problems effectively and save time and money on unnecessary repairs. Remember to budget wisely, optimize costs, and prioritize safety in all your wood processing endeavors. With the right knowledge, skills, and tools, you can succeed in your wood processing or firewood preparation projects and enjoy the satisfaction of working with wood.
