You don’t relish hauling out your snowblower in the bitter cold to tackle those six inches of snow that fell last night because you don’t have a lot of confidence you can get the machine started. But you dutifully maneuver the snowblower out of the garage or storage shed and are relieved when you actually fire up the engine after two or three tries. Okay, this chore is doable you think as you take your first pass down the driveway, the snowblower cleanly propelling the snow out the chute. But then the engine sputters… and stalls. Uh-oh, the moment you were dreading has come to pass. While you may be cursing the fact that you live in a climate that has this kind of seasonal weather, let Repair Clinic offer you some guidance on what to do when your gas-powered snowblower starts… then stops.
The power for every gas-powered snowblower is the engine
As your repair partner, Repair Clinic knows that a little knowledge goes a long way. To help you troubleshoot why your gas-powered snowblower stalls soon after you get it started, let’s review how a snowblower engine works.
Most snowblowers use a four-cycle engine to operate
Gasoline-powered snowblowers, or snow throwers if you prefer to identify the equipment that way, use a four-cycle engine to operate. Just like a car engine, a snowblower’s four-cycle engine draws gas from a fuel tank for combustion and has a separate sump for oil to keep the engine properly lubricated.
Larger engines will often have an electric start feature. Turn a key or press a start button and the engine will turn over. Smaller engines require a little more effort as you will need to pull a starter rope to turn the engine over.
The rotation of the flywheel and the linear movement of the piston starts the ignition process
When the starter rope is pulled or the electric start feature is activated, the starter engages a drive cup attached to a flywheel which rotates the engine’s crankshaft. The crankshaft connects to a piston which moves up and down within a cylinder as the crankshaft is turned. The rotation of the flywheel and the linear movement of the piston is what starts the ignition process. The flywheel has permanent magnets built into it and as it rotates past an ignition coil a magnetic field is created. This magnetic field induces electricity allowing the ignition coil to send voltage to a spark plug.
The four-cycle engine achieves combustion using four strokes
As the rotating flywheel generates that magnetic field, the engine’s intake valve opens as the piston travels down the cylinder, creating a vacuum that draws fuel and air through the engine’s carburetor where the two mix before entering the cylinder. This action is called the intake stroke of the engine and is the first of four strokes that allow a four-cycle engine to achieve combustion.
The second stroke is called the compression stroke. During this stroke, the intake valve closes and the piston travels back up to the top of the cylinder. The spark plug, which has received voltage from the ignition coil, now fires and ignites the fuel and air mixture. This small explosion pushes the piston back down the cylinder in what is called the power stroke, the third stroke of the engine.
The momentum of the spinning flywheel provides enough force to drive the piston back up the cylinder for the fourth stroke: the exhaust stroke. During this final stroke, an exhaust valve opens and the combustion gases exit through the muffler. The snowblower engine will repeat these four strokes until the engine is shut off… or until it stops on its own because of a problem with the engine.
There are generally three reasons for why a gas-powered snowblower’s engine will stall soon after it’s started. We’ll list them in the order of most likely to somewhat less likely, but you should investigate all three since there may be more than one problem affecting the engine:
- Restricted carburetor – Regardless of the quality of fuel you’re putting into the snowblower’s fuel tank, there are certain ingredients in the fuel which will evaporate and leave behind a thick, sticky residue. This residue can create a restriction in the carburetor which can stop new fuel and air from entering the engine. A carburetor that is only partially restricted may allow the engine to start but can cause it to stall shortly after. Repair Clinic recommends you first try cleaning out the carburetor ports with carburetor cleaner to eliminate this restriction. If cleaning proves to be ineffective, consider purchasing a carburetor repair kit to replace the components that are caked in residue, or you may want to just install a new carburetor.
- Clogged fuel tank cap – As the fuel is consumed the gas level in the fuel tank lowers. To avoid creating a vacuum, fuel caps will have small vent holes to allow air into the tank so the remaining fuel can be easily drawn through the carburetor. If the vent holes become clogged with residue or debris, a vacuum will be created which can cause the snowblower engine to stall. You can attempt to clean out the vent holes, but it is far easier to simply purchase a new fuel tank cap.
- Defective spark plug – Due to carbon build-up and a weakened electrode, the spark plug will degrade over time which can cause the snowblower’s engine to stall while the equipment is in use. You should first inspect the spark plug for any damage or wear. If the spark plug appears corroded, you can be pretty sure the component has the potential to intermittently fail. Even if the spark plug appears to be in good condition, Repair Clinic encourages you to replace an old spark plug with a new one annually, just prior to the snow removal season.
Need a new spark plug or carburetor for your snowblower engine? Or a new cap for the engine’s fuel tank? Repair Clinic recommends using genuine original equipment manufacturer (OEM) parts for a successful repair. OEM parts are specifically designed to work with your snowblower, so you’ll know the part will be compatible (and will likely last longer than a cheaper knock-off version). Whether you use a snowblower built by Craftsman, Toro, Ariens, Honda, MTD, Troy-bilt, Cub Cadet, or any other top manufacturer, you can find fully compatible OEM parts at Repair Clinic. Just enter the full model number of the snowblower, or the snowblower’s engine, in the Repair Clinic search bar, then use the “Part Category” (i.e. “Tank & Container”) and “Part Title” (i.e. “Fuel Cap”) navigation filters to identify the exact part you need to fix the machine.
DIY repair help is free at Repair Clinic
Are you a do-it-yourselfer when it comes to repairing outdoor power equipment? DIY repair help is free at Repair Clinic. Just visit the website’s “Videos & Articles” section to learn the correct step-by-step procedure to replace a carburetor on a model 31AM63TR756 Cub Cadet snowblower engine or how to use an ignition tester to determine if that engine’s spark plug is faulty. The Repair Clinic content library has thousands of “How To” videos, step-by-step guides, and product schematics covering lawn and garden equipment, heating and cooling systems, and all major home appliances. Just enter the full appliance or equipment model number to get started.