Snowblower Starts But Won't Move

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:

  1. Drive belt loose/ broken
  2. Broken drive bolt
  3. Drive cable loose/ broken
  4. Friction wheel worn
  5. 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.

Mower gas cap

Vented Gas Cap

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 system we'll diagnose in this post.

Some higher end snowblowers may employ a more sophisticated hydraulic system. It's known as hydro static 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 do:

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 tensioned 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 handle bars 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 across the spinning drive plate.

The friction wheel (drives the wheels) is attached to the selector. The farther the friction wheel is moved to the outer rim of the spinning drive plate, the faster the snowblower moves.

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 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 means the pavement.

The drive axle is driven by a gear on the Hex shaft, some snowblowers use a gear coupling and some may use a chain coupling. The gear is fixed to the axle by way of bolt or pin. The final components are of course the wheels.

Vented mower gas caps

Vented gas caps

Diagnosing snowblower drive system fault

Successful diagnoses 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 have their own diagnostic check. However, you can short cut 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

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.

Diagnosis

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 – smell of rubber and possibly smoke
  • Glazing – slipping drive when hot
  • Contamination – constant slip

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
  • Remove belt cover (located between the  engine and auger housing)

Locate the belt – The drive belt is located closest 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

Adjusting 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 tensioner is employed.

The tensioner is fitted with a pulley which applies all that tension to the belt. A tensioner pulley is known as an idler.

A loose belt causes slip and slip causes 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, not all drive belts are adjustable. In many cases the spring loaded tensioner takes up belt slack automatically.

A worn out or weak tensioner spring can also allow a drive belt to slip. In addition as a belt ages it gets longer, this in effect causes further slip. If in doubt, replace the belt.

Adjust belt tension as follows:

  • With belt cover removed
  • Locate the belt tensioner idler pulley
  • Loosen the idler axle bolt (bolt slides to adjust)
  • Have a helper use a suitable tool to lever the idler towards the belt
  • Tighten the idler bolt

Replacing drive belt

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 manufacturers specs as apposed to replacing with the match of the old belt. The old belt may not be correct.

Remove drive belt as follows:

  • Remove plug wire
  • Place plastic sheet over gas tank neck and refit gas cap
  • Remove the belt cover (between engine & auger)
  • Remove auger belt (belt closest the auger) from engine pulley (roll belt across pulley and crank engine by hand)
  • Set the auger belt to the side
  • Pull drive belt tensioner back and remove drive belt from crank pulley 
  • Tilt blower onto bin
  • Remove belly pan
  • Locate the drive belt and remove it from drive plate pulley

Refit drive belt as follows:

  • Feed new belt around engine drive pulley first (Blower on wheels)
  • Feed belt excess between the drive plate pulley and body
  • Tilt mower onto bin
  • Feed belt under friction wheel and seat into drive pulley
  • Place blower back on wheels
  • Pull drive tensioner back and feed belt behind tensioner pulley
  • Refit belly pan
  • Refit belt cover
  • Remove tank plastic and refit plug wire

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 diagnoses and fix is easy - access the the axle, verify the fault and replace the bolt.

The process is as follows:

  • Remove plug wire
  • Place plastic sheet over gas tank neck and refit gas cap
  • Tilt blower onto 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 fastener

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.

Adjust the drive cable

Most cables have an easily accessible adjuster hidden behind the dash panel. The adjusting process is as follows:

  • Locate the adjuster
  • Using two wrenches, open the lock nut
  • Tighten the cable so as to remove slack from the cable – check drive application
  • Tighten lock nut

Replace the drive cable

Replacing the cable isn’t very challenging but we will need to tilt the blower up onto it’s bin.

The process is as follows:

  • Remove plug wire (twist & pull) Place plastic sheet over gas tank neck and refit gas cap (prevents spill)
  • Tilt snowblower forward onto bin
  • Remove belly pan
  • Locate the drive cable and unhook it from the drive plate
  • Pull the cable clear of the and unhook the cable from the handle

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 a visual and to access the friction wheel we'll need to tilt the blower onto the bin and remove the belly pan.

Diagnosis process is as follows:

  • Remove plug wire (twist & pull) Place plastic sheet over gas tank neck and refit gas cap (prevents spill)
  • Tilt snowblower forward onto bin
  • Remove 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:

  • Locate the Hex shaft
  • Remove Hex shaft bolts (one either side)
  • Slide shaft to release
  • Move to a work bench & remove friction wheel from Hex shaft by sliding it
  • Remove friction wheel bolts
  • Remove friction wheel sandwich plate
  • Remove the 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.

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 of 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:

  • Remove plug wire (twist & pull) Place plastic sheet over gas tank neck and refit gas cap (prevents spill)
  • Tilt snowblower forward onto 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 axle, clean off the excess and use small amount of low temperature grease (00) instead.

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Auto Technician and Writer at Lawnmowerfixed | Website

John Cunningham is an Automotive Technician and writer on Lawnmowerfixed.com. I've been a mechanic for over twenty years, I use my knowledge and experience to write "How to" articles that help fellow gear-heads with all aspects of mechanical repairs, from lawn mowers to classic cars.