December 7, 2022

How to replace a snowblower spark plug

How to replace a snowblower spark plug

The snowblower spark plug creates the spark that ignites the fuel to start engine. If deposits build up on the spark plug electrode or if the ceramic insulation cracks, the spark plug won't create the spark. Fortunately, replacing a spark plug is an easy and inexpensive fix. This step-by-step snowblower repair guide shows how to install and gap a new spark plug using the manufacturer-approved snowblower part.

If the spark plug fouls quickly after you replace it, then engine problems could be apparent.

You’ll typically see either carbon deposits or oil deposits fouling the spark plug. The type of spark plug fouling often points to engine problems that you can resolve to prevent frequently having to replace the spark plug in your snowblower.

Carbon spark plug deposits

Carbon spark plug deposits are typically caused by:

  • Rich fuel mixture from a faulty carburetor.

  • Ignition system timing problems.

  • Faulty ignition system.

  • Prolonged idling.

  • Using the wrong spark plug.

Resolve these types of issues to prevent excessive carbon deposits on the spark plug.

Oil spark plug deposits

Oil deposits on the spark plug can be caused by overfilling the engine with oil or worn piston rings.

Check these issues when you see oil deposits on the spark plug.

Find additional tips for checking the snowblower spark plug in our How to check and replace a snowblower spark plug article/video.

Use these easy DIY instructions to replace the spark plug in Craftsman, Husqvarna, MTD, Murray, Honda, Toro, Yard-Man and Ariens snowblowers.

Quick links
Tools required
Spark plug gap gauge
Socket that fits the spark plug
Ratchet
Small hammer (optional)
Repair difficulty
Time required
15 minutes or less
Repair difficulty
Time required
15 minutes or less
How to replace the spark plug in a snowblower engine

Instructions

  1. 01.

    Remove the spark plug

    Disconnect the spark plug wire. Use a deep socket and a ratchet to remove the spark plug from the cylinder.

    PHOTO: Remove the spark plug.

    PHOTO: Remove the spark plug.

  2. 02.

    Gap the new spark plug

    Check your owner’s manual for the correct gap setting. Insert the gap gauge between the electrodes on the spark plug. The gap gauge should fit snuggly between the electrodes; when you pull it out, you should feel only slight resistance. If the gap is too wide, lightly tap the electrode on a clean, hard surface or use a small hammer. If the gap is too small, use the bender on the gap gauge to widen it. 

    PHOTO: Gap the spark plug.

    PHOTO: Gap the spark plug.

  3. 03.

    Install the plug

    Thread the spark plug into the cylinder. Hand-tighten the spark plug until it’s snug and then use the ratchet and deep socket to tighten the spark plug another ¼ to ½ turn. Don’t overtighten, because the steel base of the spark plug can strip the softer aluminum threads on the cylinder head.

    Reconnect the spark plug wire.

Warning: Undertaking repairs to appliances can be hazardous. Use the proper tools and safety equipment noted in the guide and follow all instructions. Do not proceed until you are confident that you understand all of the steps and are capable of completing the repair. Some repairs should only be performed by a qualified technician.

Symptoms for gas snowblowers

Choose a symptom to see related snowblower repairs.

Main causes: dirty carburetor, clogged fuel filter, dirty spark plug, incorrect valve lash, leaky engine gaskets
Main causes: dirty carburetor, stale fuel
Main causes: loose drive clutch cable, damaged drive clutch cable, worn friction disc, scraper blade scraping the ground, engine problems
Main causes: punctured tire, damaged rim
Main causes: broken shear pins, worn or loose auger drive belt, auger drive cable failure, damaged auger, bad gear case
Main causes: stale gas, clogged carburetor, clogged or broken fuel line, dirty spark plug, bad rewind starter, incorrect valve lash
Main causes: clogged chute, snow build-up in auger housing, broken auger shear pins, auger drive belt needs adjustment, auger cable problems
Things to do: replace the spark plug, change the oil, rebuild the carburetor, adjust valve lash, adjust or replace the belts
Main causes: clogged chute, damaged auger blades, broken shear pins, worn auger belt, damaged gear case, engine problems

Repair guides for gas snowblowers

These step-by-step repair guides will help you safely fix what’s broken on your snowblower.

How to replace a snowblower fuel filter

Replace the fuel filter on your snowblower if it's clogged or damaged.

Repair difficulty
Time required
 15 minutes or less
How to adjust snowblower skid shoes

To prevent snowblower auger and shave plate damage, adjust the skid shoes regularly to keep the shave plate ¼-inch high. It's an easy adjustment that you can handle yourself.

Repair difficulty
Time required
 15 minutes or less
How to rebuild a snowblower carburetor

Rebuild the carburetor on your snowblower if the engine isn't getting fuel.

Repair difficulty
Time required
 45 minutes or less

Articles and videos common to all snowblowers

Use the advice and tips in these articles and videos to get the most out of your snowblower.

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