When Your Chainsaw Won’t Start With the Spark Plug Installed

I know how frustrating it can be when you go to start your chainsaw and it won’t pull with the spark plug installed. A non-starting chainsaw can really put a wrench in your plans if you need to get some cutting done.

But don’t worry, with some basic troubleshooting and maintenance you can get your chainsaw going again. Here’s my guide to figuring out why your chainsaw won’t start even with the spark plug in place and tips to get it running properly.

Key Causes For Lack of Starting With Spark Plug

When your chainsaw won’t start even with a spark plug installed, there are a few key culprits to investigate first:

Fouled or Faulty Spark Plug

The most obvious issue is that the spark plug itself could be bad. If the spark plug is wet with fuel, covered in carbon deposits, or just defective, it can easily prevent the engine from igniting properly. I’d recommend removing the plug and inspecting it carefully.

Look for any external fouling or damage. You can also test the plug with a spark tester to see if it is still sparking correctly. If the plug is fouled or faulty, just replacing it with a fresh plug can get your saw starting again.

Engine Flooding

Another common reason a chainsaw won’t start with a spark plug is because the engine is flooded with excess fuel. This can happen if you used the choke when warm restarting or pulled the cord too many times with the choke on.

The spark simply can’t ignite in an overly fuel-rich environment. Clearing the fuel out by removing the plug and cranking the engine over without the plug can help. Let the saw sit for a few minutes before reinstalling the plug and trying again.

Carburetor Issues

Carburetor problems like a stuck choke, improperly adjusted mixture screws, or a clogged fuel passage can also prevent starting. Your carburetor may need a thorough cleaning or tuning to fix any issues that are contributing to poor starting with the plug in place.

Ignition or Compression Problems

While less common, lack of spark or low engine compression can also be the culprit. Testing your ignition coil and wires can verify if the spark is actually getting to the plug. A compression test can tell you if your cylinder pressure is in spec.

So in summary, issues with the spark plug itself, engine flooding, carburetor malfunctions, ignition failure, or loss of compression are the most likely causes for a chainsaw not starting even with a good spark plug installed. Now let’s talk about some solutions.

Tips for Improving Starting with Spark Plug-In

Here are some of my best troubleshooting tips for getting your chainsaw reliably started when you have a spark plug installed:

Use the Proper Starting Technique

The starting procedure for a chainsaw is very important. Your owner’s manual should outline the steps. Generally, you adjust the choke for the temperature, pull the cord 4-6 times to prime, push the decompress valve, and then pull hard while easing off the choke. Doing this improperly can lead to a flooded engine and prevent starting.

Check Fuel Quality and Mixture

If your fuel is old, dirty, or not premixed at the right ratio, it can definitely cause starting issues. Stale fuel or an improper gas-to-oil mix are common culprits. Only use fresh 89+ octane gas and quality 2-stroke oil at the recommended proportions.

Replace Air Filter and Spark Plug

A simple air filter or spark plug replacement can work wonders for starting difficulties. An air filter clogged with sawdust restricts airflow to the engine. And spark plugs gradually wear out over time. Fresh replacements ensure peak performance.

Read: Your Chainsaw Won’t Start With the Spark Plug

Maintain Proper Chain Lubrication

This one is often overlooked, but a dry chain and bar can drastically increase the drag on the engine, making it much harder to start. Check that the bar oil tank is full and the oiler holes are clear.

Sharpen the Chain and Check the Bar

Similarly, a dull chain makes the engine work much harder when trying to start. Keeping the cutters properly sharpened will improve starting. And replace a worn bar if the rails are badly grooved.

Adjust Carburetor Settings

If cleaning the carb doesn’t solve your issues, the high and low-speed mixture screws may need adjusting. Very minor tweaks can optimize the fuel-air ratio for easy starting.

Advanced Tuning Mods

As a last resort, you can tweak the carburetor further, modifying the high-speed jet for increased flow. Installing an adjustable ignition module also allows customizing the timing and RPM limits.

Outlining proper starting procedures, replacing worn parts, checking fuel delivery, and tuning the engine can all help solve stubborn starting issues with the spark plug installed.

Read more: Is Your Chainsaw Hard To Pull?

Specific Steps for Diagnosing and Fixing the Problem

Troubleshooting a chainsaw that won’t start even with a good spark plug requires some deductive tinkering and a process of elimination. Here are the systematic steps I would recommend:

1. Remove and Inspect the Spark Plug

The first logical step is pulling out the spark plug and giving it a visual check. Look for any external fouling from fuel or oil deposits. Check the electrode and porcelain for damage.

Test the plug with a spark tester if possible. If the plug checks out okay, move on to the next steps. If fouled or defective, replace the plug before anything else.

2. Verify Spark with a Spark Tester

Using a simple spark tester, you can clip the tester lead onto the plug boot and crank the saw to see if a strong spark is being generated. This will confirm that the ignition components are working properly. No spark means testing the stop switch, coil, wire, and flywheel magnets.

3. Ensure Proper Compression

A compression tester gauge inserted into the spark plug hole will measure the cylinder pressure as you pull the cord. The manual will specify the minimum PSI needed. Low compression can prevent starting and indicates worn piston rings or cylinder damage.

4. Check for Engine Flooding

Remove the plug and turn the engine over 5-6 times to clear out any excess fuel in the cylinder. Let sit for several minutes before reinstalling the plug and trying to start again. If it was flooded this should allow starting.

5. Examine the Carburetor

A common problem is dirt, debris, or residue clogging the carburetor passages. Remove the air filter and spray carb cleaner through all the ports and jets. Adjust the needles and try starting after cleaning.

6. Test the Ignition Coil

Use a multimeter to test the ignition coil’s primary and secondary resistance values based on your saw’s service manual. Out-of-spec readings indicate a bad coil. Replace if needed.

7. Replace the Fuel Filter

A restricted fuel filter reduces fuel flow to the carburetor. Swapping in a new fuel filter can fix starting issues.

8. Check the Flywheel Key

If the engine backfired, the flywheel key shearing could throw off ignition timing. Removing the flywheel lets you inspect the key. Replace if damaged.

Methodically checking each engine component using this process of elimination approach will help you get to the bottom of your starting problem. With some diligent troubleshooting, you’ll zero in on the culprit.

Helpful Tips to Prevent Future Starting Issues

Here are some handy maintenance tips to help prevent starting problems down the road:

• Use fuel stabilizer – Treat your gas with a stabilizer if the saw will sit for more than 2 weeks. This prevents varnishing of the carburetor and fuel system when gas starts to go bad.
• Replace the spark plug yearly – Regularly swapping in a new plug every season ensures a strong spark and easy starting. Mark your calendar as a reminder.
• Clean the air filter monthly – Use compressed air to blow out built-up sawdust that restricts air intake. Lightly oil the filter to trap more dirt.
• Sharpen the chain after 5-6 tanks – Keeping the cutters razor sharp reduces drag on the engine for easier starting. File every few uses.
• Adjust carb at the start of the season – Tune the high and low needles to account for seasonal temperature changes. Get the fuel mix dialed in.
• Clear debris from starter housing – Use an air compressor to blow out any sawdust around the recoil starter periodically. This prevents binding.
• Fix damage immediately – Don’t delay fixing any damage that could allow an air leak around the cylinder base. Air leaks affect compression and starting.

Frequently Asked Question

Final Statement

• Inspect the Spark Plug: Check for fouling or damage and replace if necessary.
• Address Engine Flooding: Clear excess fuel if the engine is flooded.
• Clean/Adjust the Carburetor: Ensure it’s free from clogs and properly tuned.
• Check Ignition and Compression: Verify spark and engine compression levels.
• Lubricate the Chain: Keep the chain well-oiled to reduce drag on the engine.
• Sharpen the Chain: A sharp chain eases the starting process.