Craftsman Snowblower Surging? Here’s the Ultimate Fix

There’s nothing more frustrating than a snowblower that won’t run smoothly when you need it most. If your Craftsman snowblower’s engine is surging—revving up and down on its own—you’re not alone. This common issue, often called “hunting,” is a clear sign that your machine needs attention before the next big snowfall.

Fortunately, you can often fix a surging Craftsman snowblower engine yourself with some basic tools and a little patience. This guide will walk you through the most common causes and provide step-by-step solutions to get your snowblower running like new again. Don’t let a surging engine ruin your winter; let’s get it fixed.

Why Your Craftsman Snowblower is Surging: The Root Causes

An engine surges when the air-fuel mixture is incorrect, typically running too lean (too much air, not enough fuel). This forces the engine’s governor to constantly adjust, causing the RPMs to fluctuate up and down. Understanding the specific reasons for this imbalance is the first step toward a successful repair.

Most of the time, the problem lies within the fuel system, which can become clogged or compromised over time. From old, degraded gasoline to a dirty carburetor, several culprits could be to blame. Pinpointing the exact cause will save you time and ensure you’re making the right adjustments.

The Number One Culprit: A Clogged Carburetor

The carburetor is the heart of your snowblower’s fuel system, and it’s the most common reason for a surging engine. Over time, especially if old fuel was left in the tank, varnish and gummy deposits can build up inside the carburetor. These deposits block tiny passages called jets, restricting fuel flow and causing a lean fuel mixture.

The main jet and the pilot jet are particularly susceptible to clogging. The pilot jet controls the fuel mixture at idle and low speeds, while the main jet manages it at high speeds. Even a minuscule blockage in these components can disrupt the delicate balance of air and fuel required for smooth operation.

Fuel-Related Problems Beyond the Carb

While the carburetor is often the main offender, other fuel system issues can also lead to surging. Stale or contaminated fuel is a primary contributor. Gasoline, especially fuel containing ethanol, can degrade in as little as 30 days, attracting moisture and forming deposits that clog the entire system.

Water in the fuel is another significant problem. Condensation can form inside the fuel tank, and this water can get into the carburetor bowl, preventing fuel from being drawn into the engine properly. A clogged fuel filter or a cracked, deteriorating fuel line can also restrict fuel flow and cause surging.

Governor and Linkage Issues

The governor is designed to maintain a constant engine speed under varying loads. It’s connected to the carburetor’s throttle plate via a series of springs and linkages. If these components are bent, binding, or incorrectly adjusted, the governor can “hunt” for the correct RPM, causing the engine to surge.

Sometimes, the springs can lose their tension over time or get stretched, affecting their ability to respond correctly to changes in engine speed. It’s crucial to inspect these parts for any signs of damage or incorrect setup, as a minor adjustment can sometimes resolve the surging entirely.

Step-by-Step Guide to Fixing a Surging Craftsman Snowblower

Now that you understand the potential causes, it’s time to roll up your sleeves and get to work. Follow these steps methodically, starting with the simplest fixes first. Always prioritize safety by disconnecting the spark plug before beginning any repairs to prevent accidental starts.

Step 1: Address the Fuel Situation

The easiest first step is to eliminate fuel problems. If you have old gas in your snowblower, drain it completely from both the tank and the carburetor bowl. Leaving old, untreated fuel is a common cause for issues, and if you suspect your Craftsman snowblower is leaking gas, this is a critical first inspection point.

Refill the tank with fresh, high-quality gasoline (87 octane or higher). It’s also highly recommended to add a fuel stabilizer, especially if you don’t use the snowblower frequently. This will prevent the fuel from degrading and causing problems in the future.

Step 2: Inspect and Clean the Carburetor

If fresh fuel doesn’t solve the problem, the next step is a thorough carburetor cleaning. This is the most likely solution for a surging engine. You will need basic hand tools, carburetor cleaner spray, and a small wire or micro drill bits to clean the jets.

First, remove any plastic shrouds or covers to access the carburetor. Take photos as you go to remember how everything goes back together. Carefully detach the fuel line (use pliers to clamp it to prevent spills), throttle linkages, and mounting bolts.

Once the carburetor is removed, take off the float bowl at the bottom. Be careful, as it may still contain some fuel. Inspect the bowl for any sediment or water. Next, you’ll need to clean the main jet and the pilot jet. The main jet is typically located in the center stem where the bowl nut screws in, while the pilot jet is often found on the top or side of the carburetor body.

Spray all passages and jets with carburetor cleaner. Use a thin wire or a specialized jet cleaning tool to gently poke through the tiny holes in the jets to ensure they are completely clear. Do not use a wire that is too large, as this can damage the jets by enlarging the holes. Reassemble the carburetor, install new gaskets if necessary, and mount it back on the engine.

Problem Symptom	Likely Cause	Difficulty of Fix	Solution
Engine surges at all speeds	Clogged main jet or pilot jet in carburetor	Medium	Remove and thoroughly clean the carburetor, paying close attention to all jets and passages.
Surging occurs only when not under load	Clogged low-speed or idle circuit	Medium	Focus cleaning efforts on the pilot jet and idle passages within the carburetor.
Engine runs smoothly with half choke	Lean fuel mixture due to air leak or fuel restriction	Easy to Medium	Check for cracked intake gaskets, ensure fuel cap is venting, and verify fuel flow. A carb cleaning is often needed.
Surging started after sitting for a long time	Stale fuel and varnish buildup	Easy	Drain all old fuel from the tank and carburetor, and refill with fresh, stabilized gasoline.

Step 3: Check Gaskets and O-Rings for Air Leaks

An air leak between the carburetor and the engine can also cause a lean condition, leading to surging. When you reinstall the carburetor, be sure to inspect the mounting gaskets. If a gasket is cracked, brittle, or damaged, it won’t create a proper seal.

Always use new gaskets when remounting a carburetor for the best results. Similarly, check any O-rings on the carburetor, such as the one on the pilot jet or the float bowl, for signs of wear or damage, as these can also be sources of air leaks.

Step 4: Inspect the Governor Linkage

Examine the governor springs and linkage rods. Make sure they move freely without binding and are connected correctly. If a spring appears stretched or damaged, it should be replaced. The governor system is sensitive, and even slight issues can cause erratic engine behavior.

While the engine is off, gently move the throttle linkage by hand to see if the governor responds smoothly. If it sticks or seems loose, it may require adjustment or replacement parts. This is a less common cause than fuel issues but is still a critical checkpoint.

The Impact of Ethanol Fuel on Carburetors

A factor many don’t consider is the destructive effect of modern ethanol-blended gasoline on small engines. Ethanol attracts water from the atmosphere, leading to corrosion inside the fuel system, especially in carburetors made of aluminum. This corrosive mixture can quickly clog the incredibly small passages in the pilot jet.

For older machines, this problem is even more pronounced. Using ethanol-free, high-octane fuel can significantly extend the life of your carburetor and prevent surging issues before they start. It’s a proactive step that can save you hours of repair work down the line. If you’re comparing machines, like in a Craftsman vs Ariens snowblower analysis, fuel system durability is a key factor to consider.

When to Replace the Carburetor

Sometimes, despite a thorough cleaning, a carburetor may be too damaged or clogged to function correctly. If you’ve cleaned it multiple times and the surging persists, it might be time for a replacement. Fortunately, replacement carburetors for Craftsman snowblowers are often inexpensive and readily available.

Replacing the entire carburetor can be a faster and more reliable solution than a complex rebuild. It eliminates any hidden blockages or wear that you might have missed. When ordering a new one, ensure you have your snowblower’s model and engine number to get the correct part. This can be a smart move, especially for models with known issues, much like addressing an Ariens ST1028LE snowblower’s problems with a direct component swap.

Preventative Maintenance: The Best Fix

The best way to fix a surging engine is to prevent it from happening in the first place. Proper end-of-season storage is crucial. Always run the snowblower out of fuel before storing it for the summer. This prevents gasoline from degrading and gumming up the carburetor.

Alternatively, fill the tank completely with fresh, stabilizer-treated fuel. This minimizes air space in the tank, reducing the potential for condensation. Regularly checking your fuel lines, filter, and spark plug will also ensure your Craftsman snowblower is ready to perform reliably when winter arrives.