* Drive Belt(s): This is the most likely culprit. The belt(s) that transfer power from the engine to the wheels may be broken, slipped off their pulleys, worn out, or too loose. Inspect the belt(s) carefully for any damage. Look at all the pulleys to make sure the belts are properly seated. If the belts are worn, you'll need replacements.
* Drive Clutch: The drive clutch engages and disengages the power to the wheels. This could be malfunctioning, either mechanically (worn parts, broken linkage) or electrically (if it's an electric clutch). Check for any obvious damage or binding in the clutch mechanism. This often involves a lever or cable system.
* Drive Shaft: The shaft connecting the engine to the wheels might be broken or damaged internally. This is less likely if the auger works, but possible. Inspect the shaft for bends or damage.
* Shear Pins: There might be shear pins within the drive system designed to break if the wheels encounter excessive resistance. These are safety features to prevent damage to the drivetrain. Check to see if any shear pins are broken and need replacing.
* Differential (if equipped): Some snowblowers have a differential. A problem with the differential could prevent power from reaching one or both wheels. This is less common.
* Electrical Issues (less likely): While less likely since the auger works, a faulty switch or wiring related *specifically* to the wheel drive could be at play. This is more common on electric-start or models with electric clutch components.
Troubleshooting Steps:
1. Visual Inspection: Carefully examine the entire drive system, paying close attention to the belts, pulleys, drive shaft, and clutch mechanism. Look for any obvious signs of damage, wear, or loose connections. Consult your owner's manual for diagrams.
2. Belt Check: This is the most important step. If the belt is broken or off, replace it. If it's worn, also replace it. Check belt tension as well – it shouldn't be too loose or too tight.
3. Clutch Check: Operate the drive lever (or engage the electric clutch if applicable) and feel for any resistance or binding. If it feels loose or doesn't engage properly, investigate the clutch mechanism further.
4. Shear Pin Check: Locate and inspect the shear pins. They are usually small, easily replaceable pins designed to protect the drive system from overload.
5. Manual: Consult your owner's manual. It will have diagrams and troubleshooting information specific to your Spirit snowblower model.
If you've checked all of these and the problem persists, you may need to take your snowblower to a small engine repair shop for professional diagnosis and repair. They have the tools and expertise to diagnose more complex issues.
