Snowblower Running Rough? Here’s How to Fix It Yourself

Is your snowblower sputtering, backfiring, or just not running smoothly this winter? A rough-running snowblower engine can be frustrating, but the good news is that the cause is often an easy fix. With some basic troubleshooting and maintenance, you can have your snowblower running like new again in no time.

We’ll explore the most common causes of a rough-running snowblower engine and provide tips to get it back in working order.

The information in this article may not apply to your specific appliance model. We recommend consulting your manufacturer’s documentation or contact us with any questions.

Inspect and replace the spark plug

One of the first things to check when you have a snowblower running rough is the spark plug. Spark plugs degrade over time due to normal engine wear and tear. The heat and combustion byproducts generated in the engine slowly damage the spark plug electrodes and porcelain insulator. This can lead to a weak spark or misfiring, which causes the rough running.

Here are some troubleshooting steps for inspecting your snowblower’s spark plug:

• Remove the spark plug and examine it visually. Look for signs of wear like a cracked porcelain insulator, corroded or burnt electrode, or heavy carbon deposits. Any of these indicate it’s time to replace the plug.
• Use a spark plug tester to check if the plug is still sparking properly. Attach the plug to the tester and crank the engine. There should be a strong, blue spark visible between the electrodes. No spark means the plug is bad and needs replacement.
• As a general maintenance guideline, you should replace your snowblower spark plug annually before winter. Preventive replacement ensures strong ignition and prevents rough running issues.

Replacing the spark plug takes just minutes and is very affordable DIY maintenance. Be sure to buy the exact replacement plug for your model. Using the wrong plug can lead to performance issues or engine damage over time.

Clean or rebuild a clogged carburetor

The other very common cause of a rough-running snowblower is a clogged carburetor. The carburetor mixes air and fuel to deliver the proper air/fuel mixture to the engine. Over time, some of the ingredients in gasoline can evaporate when the snowblower sits idle, leaving behind thicker, sticky deposits in the carburetor. These varnish-like deposits can restrict airflow through the carburetor passages and jets, leading to performance issues like:

• Hard starting
• Rough, uneven engine running
• Loss of power
• Engine stalling or dying

Here are some troubleshooting tips if you suspect your snowblower carburetor is clogged:

• Try using a carburetor cleaner to dissolve the deposits and clean out the carburetor without fully disassembling it. Spray the cleaner into the carburetor throat and let it soak for 15 minutes before running the engine. This may flush out the clogs and restore proper performance.
• If the cleaner doesn’t solve it, the carburetor needs to be removed and either rebuilt with a carburetor rebuild kit or replaced altogether. The rebuild kits include replacement gaskets, needle valves, and other parts to refresh the carburetor internals while reusing the original housing.
• As preventive maintenance, always empty the snowblower fuel or add a stabilizer at the end of winter to avoid varnish buildup over the off-season. Keeping fresh fuel in the carburetor is key to avoiding clogs.

Other possible causes

While spark plugs and carburetors account for most cases of rough running issues, here are two other problems worth mentioning:

• Engine oil overfill – The engine oil might have been overfilled. If the engine oil is overfilled, the oil may leak out through the breather and seep into the carburetor. If engine oil has seeped into the carburetor, remove the carburetor and clean it thoroughly. Then make sure that the engine has the proper level of oil.
• Sheared flywheel key – The flywheel key helps time ignition. If it shears, ignition timing is thrown off, causing rough running. Replace the key if damaged.

The Bottom Line

A sputtering, backfiring snowblower engine is frustrating, but fixing the problem is usually quite straightforward. In most cases, simply replacing the spark plug and/or cleaning the carburetor will have your snowblower running smoothly again in under an hour, for less than $30 in parts.

Before you haul the snowblower to a shop and pay for an expensive repair, take a few minutes to inspect and replace common parts like the spark plug and carburetor yourself. With millions of replacement parts and DIY repair help available online, you can easily handle most snowblower maintenance tasks.

Investing some time in preventive spark plug and carburetor maintenance before winter will help ensure your snowblower starts easily and runs smoothly all season long. Maintain your machine properly so you can focus on getting your driveway cleared instead of wrestling with snowblower issues each time it snows. Your back and bank account will thank you!

Where To Find Us 

Thank you for reading! We hope you found this information useful to get your snowblower working again.

If you need any replacement parts for your appliances, you can enter your model number at AppliancePartsPros.com to locate and order them quickly. Most orders arrive in just two business days, and we have tons of great information in our repair help section and YouTube videos to help you troubleshoot.

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