By: Author John Cunningham. Published: 2021/06/22 at 8:03 am
It’s frustrating using kit that’s just not up to the job. Snowblowers have it tough, but do they really? They only work a few months of the year, not a bad gig, and that is the root cause of your problem.
A dirty carburetor is the most common cause of a stalling snowblower engine when the auger is engaged. Cleaning the carburetor and fresh gas will fix the stalling.
In this post, you’ll learn why your snowblower stalls when the auger is applied. You’ll learn how you can fix it today and how to prevent this from happening again.
The root cause is, as you now know, most likely a lack of fuel supply. It’s known as fuel starvation. A dirty carburetor is the most common root cause of fuel starvation. Tiny fuel passages inside your carburetor become clogged and restrict gas flow.
When the auger is engaged, the engine demands more fuel; when the carburetor can’t supply it, the engine simply stalls. While the main cause of fuel starvation is a dirty carburetor fuel jet, we’ll look at other possible causes of fuel starvation too.
Although a fueling issue is the most likely cause, it’s not the only possible cause. A fault with the auger brake assembly may also cause the engine to stall when the auger is engaged. However, it is the less likely cause, so we’ll look at it towards the end of this post.
First, we’ll look at the fueling system.
For an engine to run without stalling, it needs a mix of air (oxygen) to gas ratio of 14.7:1. It’s known as the AFR (Air Fuel Ratio).
It means for every 14.7 parts of air the engine receives, it must also receive 1 part of gas.
If either air or fuel is off, the engine protests by not running at all or poorly. If the engine doesn’t get enough gas in the mix, it’s said to be running lean.
If, on the other hand, the engine isn’t getting enough oxygen, it’s said to be running rich.
In our case, we suspect we have a fuel starvation issue (lean), evidenced by the stalling engine precisely when more gas is needed (auger engaged).
What Causes a Lean Condition?
A lean condition, as you know, means there isn’t enough gas in the mix. The root cause of a lean condition is fuel starvation, but there are other causes.
Here’s a list of the more common causes of a lean condition:
- Fuel starvation (blockage)
- Faulty carburetor
- Fuel mix screw out of adjustment
- Bad gas
- E15 gas
- Gasket leaks
- Engine wear
- Valve seating issue
Common Fuel Starvation Causes
Since fuel starvation is the most common cause of our suspected problem (lean condition), we’ll look at its causes in greater detail.
In many cases, the good life may well be the cause of your snowblower stalling issue. When snowblowers retire at the end of the season, the gas in the fuel system starts to degrade.
Some owners drain the gas tank. However, it’s the gas in the carburetor bowl that’s the problem. The ethanol fuel blend we all use today begins to degrade after just a month. And degraded gas is the most likely cause of fuel starvation.
The components most likely affected include:
- Gas filter
- Gas tank
Need more info on the fuel system, carburetor components, and how they work, you can check them out here.
The diagnosis is pretty simple, remove the carburetor bowl and check the contents. Finding a gungy deposit, corrosion, or dirt means we have found our problem.
The process looks like this:
Turn the gas tap off (or pinch the gas line).
Place rags under the bowl
Remove bowl fastener
Remove gas bowl
Grit in the bowl means your carburetor likely needs cleaning
Try Cleaning The Bowl
In some cases cleaning the carburetor bowl and fuel jet will solve the issue. It’s worth a try, as cleaning the bowl and jet is a ton less labor than removing the carburetor to clean.
If your carburetor bowl employs a fastener with an integrated jet, make sure to clean it.
Snowblower Carburetor Cleaning
Cleaning the carburetor thoroughly means removing it. It is possible to spray carb cleaner into the carb, but it’s like shooting in the dark.
Removal, stripping, cleaning, rebuilding, and refitting is the best solution. However, as said it is worth cleaning just the bowl and bowl fastener (jet type) before embarking on a carb teardown. Carburetor cleaning is covered here “Snowblower only runs on choke” or check out the carburetor cleaning video here.
Snowblower Carburetor Removal
Small engines are easy to work on; for most tasks, just basic tools are needed. That’s true for this task. If you need tools, check out the “Snowblower maintenance tools page.”
Tools & products you’ll need include:
- Pliers Fuel clamp
- Ratchet & socket set
- Screwdriver set
- Wire brush
- Carburetor cleaner
- Gas stabilizer
You’ll find all these tools & products here on the “Snowblower maintenance tools page,”
The removal process is as follows:
Snowblower Carburetor Teardown
The teardown process is as follows:
Snowblower Carburetor Cleaning
To nail this task, you’ll need some carburetor cleaner and a selection of small screwdrivers, pliers and small socket set.
The cleaning process is as follows:
Snowblower Carburetor Rebuild & Fit
Rebuild in reverse order; note the following tips when rebuilding and refitting:
Adding Gas Stabilizer
To prevent this problem in the future, we have two options.
One: We can drain all the gas from the machine, including the gas bowl and fuel lines.
Two: We can add a gas stabilizer that will keep the gas fresh and protect the fuel system from gum.
The gas stabilizer is mess-free and has a lot less work. The gas stabilizer is a chemical additive we add to the gas tank to keep the ethanol from going stale or eroding the plastic and rubber components of the fuel system.
Add stabilizer as follows:
Told you it was easy!
Auger Brake Assembly
The auger is fitted with a brake to stop it quickly when the handlebar auger lever is released. The system is simple, a spring-loaded arm with a brake block attached is pushed against the auger pulley, slowing it down and stopping it when the auger lever is released. A brake is activated by way of a cable from the auger lever.
As you can imagine, if the auger brake isn’t releasing, then the engine will naturally stall. This isn’t a common problem but should be eliminated as a possible cause.
The system is simple, a spring-loaded arm with a brake block attached is pushed against the auger pulley, slowing it down and stopping it when the auger lever is released. A brake is activated by way of a cable from the auger lever.
Check out the auger component overview here.
Checking the brake as follows:
Turn gas off (if fitted)
Place a plastic sheet over the gas tank neck and refit the gas cap (prevents spill)
Turn blower up and on to bin (auger housing)
Remove belly pan
Have a helper activate the auger lever while you check the auger brake clearance
The brake block should be clear of the auger pulley when the auger lever is applied. If not, go ahead and adjust it so that it does. Adjusting is covered in the following post “Auger stops in snow.”
- 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.