Moving snow is tough, we only realize just how tough when the blower breaks down, and we are reunited with our trusty snow shovel. But for most folks, moving snow old school just isn’t an option; anyhow, I’m a mechanic, and I’ll bet we can fix your snow blower right now.
The number one common cause of snow blower no start is bad gas, but there are other possible causes; they include:
- Carburetor issue
- Spark plug issue
- Ignition coil issue
- Broken cable
- Flat battery
- Loose battery terminals
- Faulty starter solenoid
- Faulty starter motor
- Stuck valve
In this post, you’ll learn about common snowblower no-start causes, how to diagnose them and how to fix them.
It is worth pointing out early in the game – A snowblower that doesn’t start after sitting idle over the summer months likely suffers from stale gas; draining the gas tank and refilling with fresh gas fixes that problem. If that sound like a fair description of your situation, you can jump on down to the fuel system; if not, keep reading.
Index
- Starting a snow blower
- Basic checks
- No start snowblower symptoms
- Diagnosing no-start snowblower
- Ignition system diagnosis
- Fuel system diagnosis
- Compression diagnosis
- Sum up
Starting a Snow Blower
I know you know how to start a snow blower; you’ve been doing it for years, but for all the folks that may be new to the chore, here’s the detail on starting your snow blower.
First off might be helpful to know that all engines struggle to start in colder temperatures, and the reason is simple, colder temperatures mean the air is denser – denser, meaning there is more oxygen in the air.
And you’ll see why that’s a problem when you understand how a snow blower carburetor works.
Gas engines don’t run on gas alone, they require oxygen also, but they require a very precise ratio of one to the other for your engine to start and run at its best. The sweet spot is 14.7 to 1. (14.7 parts oxygen to 1 part fuel); this ratio is known as the AFR or Air Fuel Ratio.
And it’s your carburetor’s job to make sure this ratio is just right. Your carburetor is a precision instrument, and it’s been factory tuned to measure and mix air to fuel to a precise proportion.
If the proportion of air to fuel changes, you’ll know about it pretty quickly. Your engine will either fail to start, stall or struggle to move snow.
A gas engine is said to be running in one of these three conditions:
- Running lean – Too much oxygen in the mix
- Stoichiometric – Just right 14.7 to 1
- Running rich – Too much gas in the mix
The most common condition associated with cold starting is a lean condition. Meaning there isn’t enough fuel in the mix. To combat this, snowblowers are fitted with cold start features such as choke and fuel primer. Many snowblowers are fitted with both, and we’ll cover them below.
Choke
All snowblowers are fitted with a choke. A choke is a control lever or knob used to activate a choke plate. When engaged, the plate chokes off or limits the air supply and, at the same time, increases fuel to the engine.
The effect creates a richer condition which is the perfect fuel mix for starting a cold engine.
Primer bulb
Many a snowblower will have both a choke and a primer bulb. Operating the rubber bulb causes fuel to squirt directly into the carburetor’s throat. This reduces the crank time to start a cold engine. You’ll still need to operate the choke lever as an engine will need some choke until it heats up.
The primer bulbs’ main function is to aid the initial start procedure.
Starting a Snow Blower From Cold
When starting a snowblower from cold in cold weather conditions, we’ll need to richen the fuel mixture, and to do we’ll use the choke control lever and also a primer bulb if fitted.
The process is as follows:
- Check oil level
- Turn gas tap On
- Turn ignition On
- Set choke to full
- Set throttle to full (if separate control)
- Press primer bulb 3 to 4 times
- Pull start, or use the start button or plug-in electric cord
- Move choke back to a three-quarter position
- As engine heats reduce choke proportionally
- When warm, the choke should be fully off
Running a warm engine with choke On full will cause sputtering.
I wrote a post about snowblower choke use, and you can check it out here.
Starting a Snow Blower From Hot
Starting a warm engine is a ton easier. That said, you’ll likely still need to use a little choke, but usually no need to add the additional primer shot of gas.
Basic Snow Blower No-Start Checks
In this section, we’ll check all those often overlooked, easy-to-fix solutions for a no-start. It makes sense to check these first that way, we could save ourselves a ton of time and effort.
Here’s the checklist in order of commonality:
- Fuel turned On
- Fuel in the gas tank
- Ignition set to On
- Follow the correct start procedure (covered above)
- Plug wire On OK
If none of the above helped, we’ll need to roll the sleeves and dig a little deeper.
No-Start Snow Blower Symptoms
An engine needs three ingredients to start and run; it needs a good:
A no-start fault means there’s a fault with one of these systems, but which one?
A common diagnosis approach is to gather all available information that may help indicate which system has failed. The type of symptoms your machine exhibits usually offers the very best clues. I’ve included a table of common symptoms below.
Sometimes, symptoms don’t narrow down the field, and sometimes, symptoms point to a possible failure in two or all three systems, which obviously isn’t helpful.
In such instances, we’ll need to move to a top-down approach to our diagnosis. A top-down approach typically involves testing each system systematically, which can be time-consuming, but not to worry, I have you covered. If you need to run a top-down approach, I’ll share a mechanics hack here.
But first, we’ll quickly cover the different types of snowblower starting systems and how they affect diagnosis; we’ll look at them next.
What type starting system?
While snowblower engine symptoms and diagnosis are largely the same, the range of starting systems fitted are completely different, as is diagnosis.
Typically there are three different starting system types, they are:
Each starting system offers its own set of symptoms, and now, we’ll take a look at each of them in turn.
Pull cord starting system description & symptoms
A pull starter is the basic starter type, and many electric start snowblowers are fitted with a pull cord starter also. Pull cords do give issues, but generally, they are pretty obvious issues. Anyhow, here’s a list of pull cord symptoms together with the fix:
| Symptom | Possible Issues |
| Pull cord hard to pull | Engine oil over full; Hydro-locked engine; Crankshaft obstruction; Drive belt engaged; Auger engaged |
| Pull cord catches but won’t turn over the engine | Engine seized; Hydro-locked engine; Crankshaft obstruction; Drive belt engaged; Auger engaged |
| Pull cord won’t catch | Pull assembly pawls worn out |
| Pull cord won’t retract | Pull recoil spring broken |
| Pull cord snaps back | Possible broken shear key |
Check out this video; it covers common pull cord issues “Pull cord common faults video.”
Battery & starter system description & symptoms
This system includes an onboard battery, solenoid, starter motor, and starter switch, some of the links.
| Symptoms | Possible Issues |
| Engine turns over slowly | Loose/dirty battery terminals; Faulty/flat battery; Too much oil; Auger engaged; Drive engaged |
| Engine just clicks | Faulty solenoid; Flat/faulty battery; Compression release issue; Valve lash issue |
| Engine clicks repeatedly | Faulty/flat battery; Loose/dirty battery terminals |
| The engine won’t crank over -no sound | Faulty/flat battery; Loose/dirty battery terminals; Blown fuse; Ignition wiring issue |
Electric cord starter system description & symptoms
This system includes a starter motor and starter cord which is plugged into the household power supply to start the engine.
| Symptoms | Possible Issues |
| The engine won’t crank over | Cord issue; Household power supply issue; Starter motor issue |
| Engine turns over slowly | Damaged cord; Faulty starter motor |
Diagnosing a No-Start Snow Blower
You’ve looked at the common snowblower no-start symptoms, and they didn’t help any, and now let’s try the top-down diagnosis approach. As promised, I’ll show you a mechanics hack to short-circuit the laborious task of testing each of our three systems systematically.
Gas Shot
This test is an elimination round, and to nail it successfully, we’ll need the following tools and supplies:
- Plug spanner
- Funnel
- Fresh gas
The mechanics gas shot hack is as follows:
- Remove the spark plug
- Use the funnel to help add a cap full of fresh gas to the cylinder
- Refit the spark plug
- Attempt to start the engine
If you need a little more help, you’ll find a gas shot video here.
Two outcomes are likely:
1 The engine started or attempted to start – If this sounds like you, you likely have a fueling issue, go ahead and jump to fuel system repairs here.
2 The engine did not attempt to start – If this sounds like you, you may have a compression system issue. However, an ignition system issue is far more likely, so best to start by checking for spark.
1 Ignition System
The ignition system has two important jobs, they are:
- Create a strong spark
- Deliver spark at just the right time
Get either of these important jobs wrong, and the magic won’t happen. Below you’ll find a list of the ignition components, a brief description of their function, and an internal link to the diagnosis.
The ignition system consists of the following components:
- Spark plug – Causes the voltage to jump the plug gap creating the all-important spark
- Coil wire – Transports the voltage from the coil to the plug
- Coil/armature – Creates the voltage needed to fire the plug
- Flywheel – Rotating flywheel magnet excites the coil generating a voltage
- On/Off ground switch – Removes or applies ground to the coil, which controls coil voltage
- Battery & starter/ pull cord – Turns over the engine over 400rpm to create a sufficient spark
Symptoms – Typical ignition system fault symptoms include the following:
| Ignition System Symptoms | Possible Issue |
| No start | Fouled/faulty plug; Faulty coil; Weak battery/starter |
| No spark | Fouled/faulty plug; Faulty coil |
| Starts & runs until hot, then stalls | Faulty coil |
| Won’t start when hot | Faulty coil |
| Misfiring | Fouled plug; Faulty coil; Wiring issue |
Tools – To test the ignition system successfully, we’ll need an inline ignition system tester; you’ll find the one I recommend here on the “Small engine repair tools page.”
Diagnosis – When diagnosing the ignition system, our focus turns to the spark plug first, and for a good reason. The plug is under the most stress and is, therefore, the most likely failure point. But the plug is also really easy to access and check, so it makes sense to eliminate it early in the game.
It is always worth having a spare plug handy for fast swap-out diagnosis; if not, reading, cleaning, and gapping the plug is often enough to restore operation.
The coil, also known as an armature, is the next most likely ignition component to fail, and we’ll cover testing below in the diagnosis section.
Following the links below will take you to a post or video where I’ve covered the repair previously. The post or video may be related to a lawnmower, but the process is identical.
The most common ignition system issues, diagnoses, and the fix are as follows:
| Issue | Diagnosis | Fix |
| Fouled spark plug | Check spark | Clean & gap |
| Wrong spark plug | Check spec | Fit correct plug |
| Faulty coil | Run inline ignition test | Replace coil |
| Faulty coil wire cap | Run inline ignition test | Replace cap |
I covered the whole process of testing the ignition system here in a video.
If your spark seems fine, go ahead and check your compression now.
2 Fuel System
Your fuel system is tasked with a few important jobs, which include:
- Store gas
- Filter the gas
- Move gas from tank to carburetor
- Hold and maintain sufficient gas in the carburetor bowl
- Meter and mix gas proportionally
Snowblower fuel systems give a ton of trouble, and it’s not because they are faulty in some way; no, it’s because our gas is blended. Gas comes with a percentage of ethanol in it. This presents a problem for all small engines as their fuel systems are open to the atmosphere, and that causes blended gas to turn stale over the idle months.
I mention this early in the diagnosis as if your fueling system is causing issues; there is a good chance fuel contamination is to blame.
Below you’ll find a list of the fuel system components, a brief description of their function, and an internal link to the diagnosis.
Fueling system components;
- Gas tank – Stores gas
- Gas cap – Vented cap
- Fuel lines – Gravity feeds gas from tank to carb
- Gas tap – Controls flow of gas
- Gas filter – Filters gas may be inline, or gas tank integrated
- Carburetor – Mixes oxygen and gas and feeds the engine
Symptoms – Typical fuelling symptoms include the following:
| Fueling System Symptoms | Possible Issue |
| No start | Bad gas; Dirty carb |
| Starts then dies | Dirty carb |
| Surging | Dirty idle jet |
| Only runs on choke | Dirty carb |
| Leaking gas | Worn float needle |
| White smoke & high oil level | Worn float needle |
Tools – We’ll need a selection of wrenches and some fresh gas. You’ll find all the fueling system tools I recommend here on the “Small engine repair tools page.”
Diagnosis – The gas shot test is the fast-track way to diagnose a fueling issue. Fueling issues, as you likely know, mostly revolve around stale gas. Blended gas is a problem for all small engine kit.
Following the links below will take you to a post or video where I’ve covered the repair previously. The post or video may be related to a lawnmower, but the process is identical.
The most common fueling issues, diagnoses, and the fix are as follows:
| Issue | Diagnosis | Fix |
| Diry fuel bowl | Inspect bowl | Clean bowl |
| Stale gas | Gas older than two months | Drain tank & bowl |
| Blocked idle jet | Check idle jet | Clean idle jet |
| Dirty carb | Inspect carburetor | Clean carburetor |
| Worn float needle | Inspect needle | Replace needle |
I covered the whole process of testing the fueling system here in a video.
3 Compression
The first two ingredients of the internal combustion engine – spark and gas are easy to conceive, but compression, what is it anyway? and how is it important?
Compression is the squeezing of the cylinder’s contents (oxygen & gas); the piston and rings push the cylinder’s contents into the much smaller space at the top of the cylinder, known as the combustion chamber.
Compressing the cylinder does three important things:
- Concentrates energy at the top of the cylinder where the spark plug lives
- Prepares the piston at the top of the cylinder, ready for the power stroke
- Heats the combustion chamber and fuel mix, perfect conditions for ignition
The compression system relies on the following components:
- Piston rings – Rings seal the cylinder
- Head gasket – Gasket seals the bock and head interface
- Valve seating – Valves open and close sequentially and create a seal when closed
- Battery & starter/ pull cord – Turns over the engine over 400rpm to create sufficient compression
Symptoms – Typical poor compression symptoms include the following:
| Compression System Symptoms | Possible Issue |
| No start | Sticking valve |
| High oil consumption | Worn rings; Head gasket |
| Blue/white smoke | Worn rings |
| Plug fouling | Worn rings |
| Misfiring | Valve issue |
| Sound of leaking air | Head gasket |
| Lean condition | Vacuum leak |
| Hanging idle | Vacuum leak |
Tools – To test compression, we’ll need a test kit; you can check the kit I recommend here on the “Small engine repair tools page.”
Diagnosis – To create compression, the cylinder must remain sealed throughout the engine cycles. Meaning if the engine leaks air, it won’t fire. Diagnosis, therefore, is mostly about making sure the engine doesn’t leak air.
Following the links below will take you to a post or video where I’ve covered the repair previously. The post or video may be related to a lawnmower, but the process is identical.
The most common compression issues, diagnoses, and the fix are as follows:
| Issue | Diagnosis | Fix |
| Sticking valve | Inspect valve | Release valve |
| Head gasket | Compression test | Replace head gasket |
| Valve issue | Check valve lash | Adjust valve lash |
| Vacuum leak | Compression test | |
| Worn rings | Wet & dry compression test |
I covered the whole process of checking compression here in a video.
Sum Up
A snowblower that doesn’t start after sitting idle over the summer months likely suffers from stale gas; draining the gas tank and carburetor bowl and refilling it with fresh gas fixes that problem. In addition, remove, clean and check the spark plug gap or replace the spark plug.
You may also find the following posts helpful:
Snowblower won’t start after summer
- About the Author
- Latest Posts
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.