Stihl Chainsaw Won t Start After Running – Tips & Solutions

Chainsaws, like Stihl’s, are essential tools for a wide range of tasks, from professional forestry to home gardening. However, they can sometimes encounter operational issues, which can be a source of frustration and inconvenience.

One common problem that users often face is the chainsaw’s refusal to start after it has been running. This issue can be both perplexing and frustrating, particularly when there is urgent work awaiting completion.

The causes of this problem can vary, ranging from simple maintenance issues to more complex mechanical faults. Understanding these causes is key to effectively troubleshooting and resolving them.

This article aims to provide a clear and comprehensive guide to demystify the reasons behind Stihl chainsaws’ starting problems. It includes a detailed, step-by-step troubleshooting guide.

Most Common Causes of Stihl Chainsaw Starting Issues

A Stihl chainsaw not starting after running can be a perplexing issue for many users. This problem can be attributed to various factors ranging from simple maintenance oversights to more complex mechanical failures. Understanding these reasons is crucial for effective troubleshooting and ensuring your chainsaw operates reliably.

1. Fuel System Issues

The most common culprit behind a chainsaw’s failure to restart is related to the fuel system.

Stale Fuel: Chainsaws are sensitive to fuel quality. Gasoline that’s been sitting in the tank for a prolonged period can degrade, leading to starting difficulties.

Clogged Fuel Filter: Over time, the fuel filter can become clogged with debris, restricting the flow of fuel to the engine. A clogged filter means insufficient fuel reaches the carburetor, impeding the start-up.

Carburetor Adjustment: An improperly adjusted carburetor can lead to an imbalanced fuel-air mix, making it difficult for the engine to start. This usually requires fine-tuning the carburetor settings.

2. Ignition System Problems

The ignition system is another critical area that can cause starting issues.

Fouled Spark Plug: A dirty or damaged spark plug can prevent the engine from starting. The plug may become coated with carbon deposits, which impedes the spark needed to ignite the fuel.

Ignition Coil Failure: The ignition coil can malfunction, particularly when hot, leading to a failure in sparking the fuel-air mix.

3. Air Flow Restrictions

Adequate air flow is essential for engine operation.

Dirty Air Filter: A chainsaw’s air filter can become clogged with sawdust and debris, restricting the airflow necessary for combustion. This can cause the engine to stall or fail to start.

Vapor Lock: This occurs when the fuel vaporizes in the fuel line or carburetor, usually due to overheating, preventing proper fuel flow.

4. Mechanical Issues

Recoil Starter Problems: If the recoil starter mechanism is faulty, it may not engage the engine properly, preventing the chainsaw from starting.

Primer Bulb Malfunctions: A damaged or malfunctioning primer bulb can disrupt the proper flow of fuel to the carburetor.

troubleshooting the chainsaw not starting

When your Stihl chainsaw won’t start after running, it’s essential to systematically troubleshoot the problem. This guide provides a step-by-step approach to identifying and fixing common issues.

Step 1: Check the Fuel System

1. Fuel Quality: First, ensure that you’re using fresh fuel with the correct oil-to-gas ratio as per the manufacturer’s instructions. Stale or improperly mixed fuel can cause starting issues.
2. Fuel Filter: Inspect the fuel filter for clogs or dirt. A clogged fuel filter can restrict the flow of fuel to the engine. Replace the filter if it’s dirty.
3. Carburetor Adjustment: Improper carburetor adjustment can lead to an imbalanced fuel-air mixture. Adjust the carburetor settings according to the manufacturer’s guidelines. This usually involves tweaking the idle speed screw and the main mixture screw.

Step 2: Inspect the Ignition System

1. Spark Plug Condition: Remove and inspect the spark plug. A dirty or damaged spark plug can prevent the engine from starting. Clean it with a wire brush if it’s dirty or replace it if it’s damaged.
2. Ignition Coil: Check the ignition coil, especially if the chainsaw fails to start when hot. A failing ignition coil may need replacement.

Step 3: Air Flow Check

1. Air Filter: Remove and examine the air filter. A dirty air filter can restrict the airflow needed for combustion. Clean the filter or replace it if it’s too soiled.
2. Inspect for Vapor Lock: If the chainsaw overheats, check for vapor lock by loosening the fuel cap to release any built-up vapors, then retighten and try starting the chainsaw.

Step 4: Mechanical Component Inspection

1. Recoil Starter: Examine the recoil starter mechanism. Ensure that it is engaging properly and not jammed or broken. Replace any damaged parts.
2. Primer Bulb: Look at the primer bulb for cracks or damage. A malfunctioning primer bulb can impede starting and needs replacement if damaged.

Chainsaw Vapor Lock and Ignition Problems

Vapor lock and ignition issues are common problems that can prevent a Stihl chainsaw from starting after running. Understanding and addressing these issues is crucial for efficient chainsaw operation.

Vapor Lock

Vapor lock occurs when fuel vapors build up in the chainsaw’s fuel system, particularly in the gas tank. This buildup creates a sort of vapor barrier, preventing the fuel from flowing correctly to the engine. Vapor lock is more likely to happen in hot weather or when the chainsaw overheats after prolonged use.

Symptoms of Vapor Lock:

• The chainsaw starts and runs fine initially but won’t start again after stopping.
• The issue temporarily resolves after the chainsaw cools down.

Fixing Vapor Lock:

• Cool Down: Allow the chainsaw to cool if it’s been running for an extended period.
• Vent the Gas Tank: Loosen the fuel cap to release built-up vapors, then retighten it and try starting the chainsaw again.

Ignition Problems

Ignition problems in a Stihl chainsaw can stem from issues with the spark plug or the ignition coil.

Troubleshooting Ignition Issues:

• Spark Plug: Inspect the spark plug for carbon buildup or damage. Clean or replace it if necessary. A dirty or damaged spark plug can impede the engine’s ability to start.
• Ignition Coil: The ignition coil can fail, especially when hot. After running the chainsaw, if it doesn’t start, check the coil. A coil that’s too hot to touch or shows signs of damage needs replacement.

Preventive Measures:

• Regularly clean and inspect the spark plug.
• Avoid operating the chainsaw for extended periods without breaks to prevent overheating.
• Schedule periodic maintenance checks for the ignition system.

Dealing with a chainsaw-flooded Engine

A flooded engine is a frequent issue with Stihl chainsaws, particularly when repeated attempts to start the chainsaw inject excess fuel into the engine. This overabundance of fuel saturates the combustion chamber, preventing the spark plug from igniting the fuel-air mixture effectively.

Symptoms of a Flooded Engine

• The chainsaw won’t start after several starting attempts.
• A strong smell of gasoline near the chainsaw.

Steps to Fix a Flooded Engine

1. Remove the Spark Plug: Carefully remove the spark plug. This step helps in ventilating the combustion chamber.
2. Evacuate Excess Fuel: With the spark plug removed, pull the starter cord a few times. This action expels excess fuel from the combustion chamber.
3. Dry the Spark Plug: Wipe the spark plug dry if it’s wet with fuel. Check for any damage or carbon deposits and clean or replace them if necessary.
4. Reassemble and Start: Reinsert the spark plug and try starting the chainsaw. A cleaner combustion chamber and a dry spark plug should resolve the flooding issue.

Preventive Tips

• Avoid over-priming the chainsaw before starting.
• Ensure the correct choke setting for starting the chainsaw.
• Limit the number of attempts when trying to start the chainsaw to prevent flooding.

Chainsaw Recoil Starter and Primer Bulb Issues

Problems with the recoil starter and primer bulb are less common but can be frustrating obstacles when starting a Stihl chainsaw. Understanding and addressing these components is crucial for a smooth start.

Recoil Starter Assembly Issues

The recoil starter mechanism is responsible for initiating the engine’s operation. If this assembly is malfunctioning, it can prevent the chainsaw from starting.

Symptoms of Recoil Starter Problems:

• The pull cord is difficult to pull or doesn’t retract properly.
• The chainsaw doesn’t engage or start when pulling the cord.

Fixing Recoil Starter Issues:

1. Inspect the Recoil Starter: Check for any visible signs of damage or wear, such as broken cords or springs.
2. Lubricate Moving Parts: Apply lubricant to the moving parts if they appear stiff or rusty.
3. Replace Faulty Parts: If any part of the recoil starter is broken, it will need to be replaced.

Primer Bulb Malfunctions

The primer bulb aids in drawing fuel into the carburetor for the engine to start. A faulty primer bulb can disrupt the fuel flow.

Symptoms of Primer Bulb Issues:

• The primer bulb doesn’t fill with fuel or has visible cracks.
• Difficulty in starting the engine even with correct fuel and spark.

Fixing Primer Bulb Problems:

1. Inspect the Primer Bulb: Look for cracks or damage.
2. Replace if Necessary: If the primer bulb is damaged, replace it to ensure proper fuel flow.

the role of chainsaw spark Arrestor

The spark arrestor in a Stihl chainsaw plays a crucial role in safety and engine performance. It is a small screen that prevents sparks from exiting the exhaust system, thereby reducing the risk of accidental fires, especially in dry and combustible environments.

Importance of the Spark Arrestor:

• Prevents Fires: Captures and contains hot sparks that could ignite dry foliage.
• Maintains Airflow: Ensures proper exhaust flow, which is essential for engine efficiency.

Common Spark Arrestor Issues:

A clogged or dirty spark arrestor can impede exhaust flow, leading to engine performance issues, including difficulties in starting.

Maintaining the Spark Arrestor:

1. Regular Inspection: Check the spark arrestor periodically for soot or debris buildup.
2. Cleaning: If clogged, carefully clean the screen with a wire brush or replace it if it’s excessively worn or damaged.

Tips for Chainsaw Preventing Future Issues

Maintaining a Stihl chainsaw properly can significantly reduce the likelihood of starting issues and prolong the tool’s lifespan. Here are key tips to prevent future problems:

Regular Maintenance

Regularly check and clean the air filter. A clean filter ensures optimal airflow, which is crucial for engine efficiency.

Keep the spark plug clean and replace it when worn. A well-maintained spark plug is essential for reliable starting.

Use fresh fuel and avoid leaving fuel in the chainsaw for extended periods. Stale fuel can lead to starting difficulties.

Proper Storage

Before storing the chainsaw for a long time, drain the fuel to prevent carburetor clogs and fuel degradation.

Remove dirt, sawdust, and debris. A clean chainsaw will be more reliable and easier to start when you next use it.

Regular Use and Checks

Frequent use helps keep the engine in good condition.

Before each use, check the fuel mix, air filter, and spark plug.

FAQs on Stihl Chainsaw Starting Issues