Moving snow is tough work, but pushing a snowblower, that’s unimaginable hardship. No, we’ll have to fix it and you’re in the right place, I’m a mechanic and I see this problem a ton.
The top five most common reasons a snowblower won’t move, include:
- Drive belt loose/ broken
- Broken drive bolt
- Drive cable loose/ broken
- Friction wheel worn
- Drive plate contamination
In this post, you’ll learn how your snowblower drive system works, how to diagnose a drive system fault, and how to fix it.
How Snowblower Drive System Works
Most snowblower drive systems are wonderfully simple, easy to access and repair. The basic drive system employs pulleys and a belt to transfer power from the engine to the wheels. It’s this type of system we’ll diagnose in this post.
Some higher-end snowblowers may employ a more sophisticated hydraulic system. It’s known as hydrostatic transmission and while power is still transmitted by pulleys and a belt, the similarities end there.
We won’t cover the hydrostatic system here, for a couple of reasons, it’s far less common, and internal parts for the transmission are not easily available.
Components of the basic snowblower drive system:
- Drive pulleys
- Drive belt
- Drive cable
- Gear selector assembly includes: Hex shaft, gear lever, sliding gear selector, bearings, and bushings
- Friction wheel
- Drive axle assembly includes: Drive axle, gear, gear pin, bearings, bushings, and wheels
And here’s an outline of what each of these components does:
Drive pulleys
A pulley attached to the engine transfers power to an integrated pulley on the drive plate.
In addition, a third pulley (known as an idler) attached to a spring-loaded arm (known as the tensioner) is employed to keep the drive belt tension between the two main pulleys.
Drive belt
The drive belt makes movement possible. It stretches between the engine pulley and the drive plate pulley. The tensioner as you know, keeps the idler pulley pushed tightly against the belt.
Drive cable
The drive cable is a braided cable shielded by a plastic outer. It reaches from the drive control lever on the handlebars to the drive plate.
When the drive lever is activated, the cable pulls the drive plate, causing it to pivoting it into contact with the friction wheel.
Gear selector assembly
The gear selector is a beautifully simple solution to gears. Shifting the gear lever slides the selector (with a friction wheel attached) across the spinning drive plate.
The friction wheel (with rubber tire-like material) is attached to the hex axle and is controlled by the gear selector. The farther the friction wheel is moved from the center of the drive-plate, the faster the snowblower moves.
Moving the friction wheel across to the opposite side of the drive plate causes the snowblower to move backways. Love that simplicity!
Friction wheel
The friction wheel has a very important job. It’s fixed to the Hex axle and transmits power from the spinning drive plate to the final drive.
In addition, it works in combination with the gear selector to change the gear ratio. The friction wheel employs a rubber material to aid traction.
Drive axle assembly
The final drive or drive axle is where the power finally meets the pavement.
The drive axle is driven by a gear on the Hex shaft, some snow blowers use a gear coupling and some may use a chain coupling. The gear is fixed to the axle by way of a bolt or pin. The final components are of course the wheels.
Diagnosing Snowblower Drive System Fault
Successful diagnosis means systematically checking over the system looking for clues as to what’s going on. I have listed the most common failures first and so it’s likely your problem is one of the first in the list.
I deal with all the likely causes below and each has its own diagnostic check. However, you can shortcut the process by doing a little detective work first:
Is the drive lever loose? – If so, suspect broken belt or drive cable or drive cable adjustment
Does the drive lever feel normal (normal tension)? – If so suspect possible drive plate contamination, broken axle gear pin, or worn friction wheel
Does the snowblower attempt to move a little? If so suspect drive plate contamination, cable adjustment, worn friction wheel, worn drive belt, or drive belt tension adjustment
Does the snowblower smell of burning rubber, smoke and not move either forward or back? – suspect belt failure
1 Drive Belt Loose/Broken
Drive belts have a tough job and for that reason are a common drive system failure point. Belts can last years but a poorly tensioned belt may burn out prematurely.
Common belt faults and their symptoms include:
- Loose – lacks drive or slips under load
- Worn – slips under load
- Breaking – no drive
- Burning – the smell of rubber and possibly smoke
- Glazing – slipping drive when hot
- Contamination – constant slip
Diagnosis
Remove belt cover – To check and diagnose a belt issue, we’ll need to remove the belt cover. The process is as follows:
Remove plug wire (pull & twist) for safety. May need to remove some plastic covers to access the plug.
Remove belt cover (located between the engine and auger housing)
Locate the belt – The drive belt is located closest to the engine. It’s the smaller of the two belts.
Check the belt is in place, if not see fitting new belt below.
Check the belt is tensioned correctly, if not adjust the idler. See below
Belt tension
Drive belts need to be taught between the pulleys. In order to keep the belt in tension at all times, a spring-loaded arm know as a tensioner is employed.
The tensioner is fitted with a pulley that applies all that tension to the belt. A tensioner pulley is known as an idler.
A loose belt causes slip and slips causes a lack of drive at the wheels. But slip also causes heat to build in the belt. Excessive heat can cause the belt to smoke and flat spot, but even a little slip can cause a belt to prematurely wear out.
It should be noted, most drive belts are not adjustable. In most cases, the spring-loaded tensioner takes up belt slack automatically.
A worn-out or weak tensioner spring however can allow a drive belt to slip. In addition as the belt ages it gets longer, this in effect causes further slip. If in doubt about your belt, replace the it. It’s all covered below.
Replacing Drive Belt
Drive belts work hard and eventually wear out. Most belts give you the heads up long before they actually break. Symptoms include smoke, vibrations, strange noises, slower than normal pace, etc. Yep, they all mean your belt is done and you’ll need to replace it.
Belt fitting is more awkward than difficult, but for sure you can do it. The correct belt size is crucial to success. An incorrect belt may cause further drive issues. I like to check the belt part number with the manufacturer’s specs as opposed to replacing it with the match of the old belt. The old belt may not be correct.
Remove drive belt as follows:
Remove plug wire and spark plug
Place the plastic sheet over the gas tank neck and refit the gas cap
Remove the belt cover (between engine & auger)
Remove belt keeper
Remove auger belt (belt closest to the auger) from engine pulley (roll belt across pulley and crank engine by hand)
Removing the spark plug makes this a ton easier.
Set the auger belt to the side
Remove drive idler arm spring and pull drive belt tensioner back
Tilt blower onto the bin
Remove belly pan
Locate the drive belt and remove it from the drive plate pulley
Reach around and remove the drive belt from the engine pulley and feed it towards the belly pan area
Maneuver the belt so that it sits under the friction wheel and force it under the wheek by both pulling the belt and turning the friction wheel simultaneously
Fit drive belt as follows:
The refit process is just the reverse of the removal process.
Feed new belt under the friction wheel
Feed belt excess belt topside, then reach around and place the belt around the engines crankshaft pulley
Belly pan side again – now fit the belt to drive plate pulley and rotate drive plate to seat the belt all the way around
Fit the belly pan
Check the belt is seated correctly in the lower, upper, and idler pulley, then fit the idler arm spring
Now fit the auger belt, by forcing the belt to ride on the edge of the pulley while cranking the engine slowly
Go ahead now and fit the upper belt keeper, plastic belt cover, refit the spark plug and wire, turn gas on and remove the plastic sheet from the gas tank. I think you are ready to play!
2 Broken Drive Axle Bolt
The final drive is driven by the Hex shaft. A gear on the Hex shaft drives a gear on the final drive (axle) causing the snowblower to propel.
The gear on the axle is fixed using a bolt or pin and they commonly break. The diagnosis and fix are easy – access the axle, verify the fault and replace the bolt.
The diagnosis process is as follows:
Remove plug wire
Place the plastic sheet over the gas tank neck and refit the gas cap
Tilt blower onto the bin
Remove belly pan
Locate the drive axle and gear
Examine the axle gear fastener
Replace the axle gear fastener as follows:
- Remove any fastener remnants
- Size both the length and diameter bolt required
- Use grade five or eight bolt
- Align the gear hole with the axle hole and fit the new fastener
3 Drive Cable Loose/broken
Drive cables stretch over time and they’ll need a little adjustment. The most common symptom of a loose cable is a lack of resistance when pulled and of course poor drive or no drive at all. A little adjustment will fix this, see below.
If on the other hand, the cable has broken, which is common also. The symptoms of a broken cable are more exaggerated. Meaning the drive handle will offer no resistance at all and obviously no drive. This as you have guessed means you need a new cable. We cover that below too.
Diagnose loose drive cable as follows:
Place snowblower in gear (engine off)
While pushing the machine forward, progressively apply the drive control on the handlebar.
When the drive cable is adjusted correctly, the wheels begin to lock when the lever to handlebar distance is approx. 20cm.
If not, adjust the cable, see below.
Adjust drive cable as follows:
Locate the drive cable adjuster nut
Open the lock nut and adjust the cable length (ad lever to handlebar distance) by turning the adjuster to either shorten or lengthen the cable as lever adjustment dictates.
Tighten the lock nut when finished.
With the drive lever at rest, the snowblower wheels should be free. If not suspect you’ve over-adjusted. Back off the adjuster until the wheels move freely.
Alternatively, remove the belly pan and check that there’s at min 1 mm between the friction wheel and drive plate.
Replace The Drive Cable
Replacing the cable isn’t very challenging but we will need to tilt the blower up onto its bin.
The belt replacing process is as follows:
Turn gas off and place plastic sheet around the gas tank
Tilt snowblower forward onto the bin
Best to use OEM parts
Remove belly pan
Remove drive plate cable end
Loosen guide
Remove handlebar cable end
Fitting is the reverse of removal, but you may need to adjust after fitting.
4 Worn Friction Wheel
Friction wheels work super hard. The traction you get at the wheels depends on how well the friction wheel performs. They wear out, crack and disintegrate with wear and age. I replace a ton of them.
Diagnosis is visual and to access the friction wheel we’ll need to tilt the blower onto the bin and remove the belly pan.
The diagnosis process is as follows:
Place the plastic sheet over the gas tank neck and refit the gas cap
Tilt snowblower forward onto the bin
Remove the belly pan, locate the friction wheel and examine.
Finding cracks, stripped, perished, or worn down material means you’ll need to replace it.
Replacing process is as follows:
Remove wheels
Remove Hex shaft bolts
Remove the carrier bearing
Take photograph before sliding the shaft out. Be mindful of loose washers.
Remove the friction wheel from the shift fork and remove the washer and pinion gear.
Pull the Hex shaft outward to release the friction wheel.
Remove the friction wheel and move to a workbench and remove the fasteners to remove the old rubber friction material.
Replacing the friction material is the reverse of removal. On reassembly, add low-temperature grease to the Hex shaft. Remember to connect the gear selector rod before tightening the Hex axle fasteners.
5 Drive Plate Contamination
The drive plate supplies the power and so it is super important it’s free from oil and grease. Dirt on the plate will obviously cause the friction wheel to slip.
Contamination is a pretty common problem. It often occurs because excess lubricate or incorrect lube was used on the gears or Hex shaft. Engine oil is another source of possible oil contamination.
Inspect and clean the drive plate as follows:
Place the plastic sheet over the gas tank neck and refit the gas cap
Tilt snowblower forward onto the bin
Remove belly pan
Locate the drive plate. Check for grease or oil contamination.
Using rubbing alcohol and a clean cloth, clean the drive plate Clean the friction wheel rubber material also
Check for the source of contamination. An engine oil leak will need to be fixed. A drive belt will sling oil onto surfaces and this problem will reoccur. If the problem was excessive grease on gears or axles, clean off the excess and use a small amount of low-temperature grease (00) instead.
- About the Author
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John Cunningham is an Automotive Technician and writer at Lawnmowerfixed.com.
He’s been a mechanic for over twenty-five years and shares his know-how and hands-on experience in our DIY repair guides.
Johns’s fluff-free How-to guides help homeowners fix lawnmowers, tractor mowers, chainsaws, leaf blowers, power washers, generators, snow blowers, and more.