How to Start a Snowblower in Seconds (Any Model)

Nothing tests your patience like a snowblower that won't fire at 6 a.m. with eight inches on the driveway and a meeting at nine. If you want to know how to start a snowblower without flooding it or snapping the cord, the answer depends on your engine and your start method. The machines are simple.

The variables around them are what trip people up.

Our research across owner's manuals from Ariens, Toro, Honda, and Briggs & Stratton keeps landing on the same three branch points: fuel mix, choke position, and starting temperature. Nearly every four-cycle unit wants 87 octane or higher and a plug gap near 0.030 in. Get those right and most machines fire on the first or second pull.

Get them wrong and you'll pull a cord twenty times on an engine that was never going to catch.

How to Start a Snowblower

Starting a snowblower comes down to four steps. Move the machine outdoors, never into a garage. Check the oil, add fresh fuel, open the shutoff valve.

Set full choke and prime if there's a bulb. Turn the key, press the starter, or pull the cord. Ease the choke off once the engine catches.

Why Snowblowers Refuse to Start on the First Storm of the Year

Your machine didn't break over the summer. It sat. That one fact explains most of the no-start calls that hit small-engine shops in the first cold snap of December.

Gasoline is a blend of volatile compounds, and the lightest fractions evaporate first. What stays behind oxidizes into gum and varnish. In a carburetor jet roughly the diameter of a pin, a thin film of that varnish is enough to block the fuel circuit entirely.

Ethanol blends make it worse. E10 pulls moisture out of humid summer air, and once it's saturated it separates into a corrosive layer sitting in the bottom of the float bowl. Fuel stabilizer slows that decay.

It doesn't undo it.

Manufacturer service guidance is consistent on the timeline: unstabilized ethanol blend starts going off in roughly 30 days. A machine parked in April and fired up in December has been sitting on eight months of that decline.

Then the cold arrives and stacks a second problem on top. Battery capacity drops, engine oil thickens, and fuel atomizes poorly in a cold intake. A marginal fuel system that would have coughed to life in October simply won't in January.

Two more things worth checking before you blame the machine. If the plug comes out wet and black, you're looking at oil fouling or a rich mixture rather than a fuel delivery fault. And resist the urge to fix a fuel problem by spraying ether straight into the cylinder.

It can wake a dry engine, but it won't clean a blocked jet, and repeated use strips oil off the cylinder walls.

Before You Touch Anything: Identify the Snowblower You're Actually Starting

Five questions decide your starting sequence. Answer them and you skip the guesswork.

Two-Cycle or Four-Cycle Engine (This Decides Your Fuel)

A two-cycle engine burns gasoline mixed with oil. A four-cycle engine has a separate oil sump and takes straight gas.

Here's how to tell them apart in ten seconds:

• Look for a dipstick or oil fill cap. If it has one, it's four-cycle.
• Check the fuel cap sticker. Two-cycle units usually carry a ratio callout like 50:1.
• Look at the engine block. A separate oil reservoir means four-cycle every time.
• Check the manual if the labels are worn. Guessing here can cost you a piston.

Putting straight gas in a two-cycle engine scores the piston and cylinder. That's not a repair, it's a rebuild or a new machine.

Recoil Starter, Electric Start, or Battery

A recoil starter is the pull cord. Electric start is a 120V starter motor bolted to a gas engine, powered through a cord from a wall outlet. Battery machines run on a removable pack and have no cord at all.

Plenty of gas units carry both a corded starter and a recoil backup. Use the electric start when you have power nearby. Save the cord for the day the outlet is buried in a snowbank.

Primer Bulb, Manual Choke, or Auto-Choke

A primer bulb squirts raw fuel into the intake throat. It's a fuel-delivery aid, not a choke, and plenty of four-cycle engines don't have one.

Manual choke engines have a lever with positions marked full, half, and run. Auto-choke engines handle the whole thing themselves. If your machine has neither a bulb nor a choke lever, don't invent one.

Just start it.

Cold Engine or Warm Restart

A cold engine needs choke. A warm engine almost never does. Restarting a hot engine with full choke is the single fastest way to flood it.

Cold means it hasn't run today. Warm means it ran five minutes ago and you stalled it on the plow berm.

Single-Stage vs. Two-Stage vs. Three-Stage Machine

This shapes how you use the machine more than how you start it, but it matters at the controls. Single-stage units use rubber paddles that must spin freely by hand with the engine off. Two-stage units have a steel auger plus a separate impeller and independent auger and traction levers.

Three-stage adds an accelerator box between them.

The Pre-Start Checklist: What to Verify Before the First Pull

Ten minutes of checks saves an hour of pulling. Run this every time the machine has been sitting, and quickly before every storm.

1. Read the manual for your exact model. Choke positions, primer counts, and oil capacity differ by engine, sometimes within the same brand.
2. Check the oil on four-cycle units. Level at the dipstick, no milky residue, no gas smell.
3. Fill with fresh fuel. 87 octane or higher, ethanol-free if you can get it.
4. Confirm the mix on two-cycle units. Fresh, correctly measured, and not last season's batch.
5. Inspect the spark plug. Clean, correct gap, boot seated firmly.
6. Check the shear pins and belts. A snapped pin means the auger won't turn even with a running engine.
7. Turn the auger and impeller by hand, engine off. They should move freely. Ice and rust love to lock them.
8. Set the chute direction before you start. Aim it away from cars, windows, and the road.
9. Move the machine to open air. Level ground, outside, every time.
10. Check the skid shoes. On gravel, set them high enough that the auger housing clears the stones.

Oil Level, Fresh Fuel, and the Fuel Shut-Off Valve

The fuel shut-off valve sits under the tank on many two-stage machines. If it's closed, the engine will pull fuel for about twenty seconds, then die. Every year, someone decides their machine is broken because of that little lever.

Fill the tank outdoors, with the engine cold and off. Fuel expands in a sealed tank, so don't top it to the brim.

Auger, Shear Pins, Spark Plug, and Chute Position

Shear pins are designed to break so your gearbox doesn't. They're cheap and they fail in exactly the conditions that make you need the machine. Keep spares on the shelf.

When you replace one, snug it down by hand and finish with a wrench. Small fasteners strip and snap fast, which is the same reason an impact gun is the wrong tool for small fasteners like these.

Check plug condition honestly. A fouled plug costs a few dollars. Chasing a fuel problem that's really an ignition problem costs a weekend.

Getting the Machine Outdoors, Every Single Time

This one isn't a tip. It's the rule that keeps you alive.

Gas snowblowers produce carbon monoxide, an odorless gas that builds up fast in a garage, shed, or any space with a roof. Opening the overhead door doesn't make it safe. The CDC's carbon monoxide guidance is unambiguous: never run a fuel-burning engine in an enclosed or partly enclosed space.

So start it on the driveway. Even in a snowstorm. Even for thirty seconds.

Branch One: Starting a Four-Cycle Snowblower with the Recoil (Pull) Starter

This is the most common machine in the snow belt and the one people fight with most. The sequence is simple if you follow the order.

Setting the Choke, Throttle, Key, and Fuel Valve

Work through it in this order every time:

1. Fuel valve open (lever in line with the fuel line).
2. Ignition key inserted and turned to run, or the switch flipped on.
3. Throttle lever to fast or run.
4. Choke lever to full.
5. Primer pressed three times, only if your engine has a bulb and only when cold.

Manufacturer specs vary on primer counts, and over-priming is a real failure mode. Three firm presses is the common figure. Five or six pushes on a mild day will flood the intake and leave you pulling with the choke on, which makes it worse.

If your engine has an auto-choke, skip steps four and five entirely. There's nothing to set.

The Pull Itself: Stance, Grip, and Technique

Stand behind the machine with both feet planted. Grip the handle with one hand, the rope with the other.

Pull smoothly and firmly through the full stroke. Don't yank, and don't let the rope snap back against the housing.

A short, sharp jerk moves the piston too slowly to build compression. A long, deliberate pull does the job. Let the rope retract on its own before the next attempt.

If the cord feels locked solid, stop. That's often hydro-lock, where fuel has pooled on top of the piston. Pull the plug, dry it, crank once with the plug out, and refit.

As It Catches: Walking the Choke Back and Warming Up

The engine will stumble and then catch. The moment it fires, move the choke to half.

Once it runs cleanly, usually ten to twenty seconds later, move the choke to off or run. Let it idle for 30 to 60 seconds before you load the auger.

Loading a cold engine is how you get a stall in the middle of the driveway with a full auger housing. Give it that minute.

Branch Two: Electric Start Done Right

Electric start removes the shoulder work, and it introduces two new failure points: the cord and the outlet. Both are easy to rule out.

Choosing the Right Extension Cord (Gauge, Length, GFCI Outlet)

A 120V starter motor draws a heavy surge for a few seconds. Undersized cord means voltage drop, and low voltage means a starter that groans, clicks, or refuses to turn at all.

Use a grounded three-prong cord in good condition. Plug into a GFCI-protected outlet, especially outdoors or in a garage. Keep the connection up off the ground and out of the snow, and never run the machine over the cord.

Pressing the Button: Sequence and Why Starters Fail to Crank

Set the choke and prime first, exactly as you would for a pull start. Then:

1. Plug the cord into the machine, then into the outlet.
2. Turn the key to run.
3. Press the starter button for no more than five seconds.
4. Wait ten seconds before trying again. The starter has thermal protection and will cut out if you hammer it.
5. Unplug the cord the moment the engine catches.

If nothing happens at all, work through the list: is the outlet live, is the GFCI tripped, is the cord damaged, is the key actually on, is the fuel valve open. A dead starter on an otherwise healthy engine is usually one of those five things.

If the starter spins but the engine won't fire, you have a fuel or ignition problem, not a starter problem. Go back to the checklist.

Branch Three: Starting a Two-Cycle Snowblower Without Seizing the Piston

Two-cycle engines are lighter, cheaper, and far less forgiving. There's no oil sump to check, no dipstick to read, and no safety net if you grab the wrong can.

These engines are usually small, often under 100 cc, and they power the compact single-stage units that are perfect for a suburban sidewalk. They also die fast when they get straight gasoline.

Mixing 50:1 Fuel (and the 40:1 / 32:1 Exceptions)

Your engine's required ratio is printed on the fuel cap or in the manual. Follow that number, not the one your neighbor uses.

Pour the oil into a clean approved can first, then add the gasoline. That order helps the oil disperse instead of sinking to the bottom and sitting there.

Shake the can before every fill. Two-cycle oil doesn't stay in suspension forever, and a stratified can delivers a lean charge on the first pour and an over-oiled one on the last.

Use a dedicated can marked for mixed fuel. Nothing ruins a piston faster than topping off a two-cycle tank from the straight-gas can you used for the lawnmower.

Priming and Choking a Two-Cycle in Real Cold

Two-cycles are cold-blooded. They run lean when the intake air is 15°F, and lean mixtures are hard to light.

So give them the fuel they need:

1. Choke lever to full.
2. Prime two to three times if the engine has a bulb.
3. Throttle to fast.
4. Pull firmly through the full stroke, up to four times.
5. Move the choke to half as soon as it pops or fires.
6. Let it run at half choke for fifteen to thirty seconds before going to run.

If it fires and dies on the second pull, you're close. Give it one more pull with the choke still on rather than reaching for the primer again. Repeated priming is how these small engines flood.

A two-cycle that suddenly loses power mid-job and won't restart usually isn't flooded. If the cord now pulls with almost no resistance, stop pulling. That's the feel of a scored piston, and more cranking only makes the damage worse.

Keep fresh mix on the shelf and old mix out of the machine. Premixed fuel stabilizes for roughly 30 days in a sealed can. Canned ethanol-free premix lasts years, which is why so many owners keep a can just for the first storm of the season.

Branch Four: Starting a Cordless Battery Snowblower

Battery machines skip fuel entirely. There's no choke, no primer, no cord, and no pull. The starting procedure is closer to switching on a power tool than firing an engine.

That simplicity has one catch. The battery is now the whole fuel system, and cold is its enemy.

Cold Batteries, Storage Charge, and Pair Management

Lithium-ion packs lose usable capacity as they chill. Our read of manufacturer spec sheets and owner reports puts the loss at roughly 20 to 30 percent at typical winter temperatures. A pack that clears a two-car driveway in October may not finish the same job in February.

What works in practice:

• Store packs indoors. A 68°F pack out of the house beats a 20°F pack out of the shed every time.
• Charge before you go out, not after. Most packs charge best at room temperature.
• Carry the spare inside your coat. Body heat keeps it in its happy range.
• Run both packs down evenly. Swapping early beats running one to cutoff.
• Watch for a self-discharge dip. Packs left idle for months drift down and may need a top-up before the season.

Off-season, store packs at roughly 40 to 60 percent charge. Full-charge storage ages cells faster, and dead-flat storage can brick a pack permanently.

Starting the Machine in Three Motions

Press the safety button or insert the key. Squeeze the auger lever, then the drive lever. That's it.

Most cordless units won't spin the auger until the safety switch is engaged, which is why a "dead" machine is usually just a missing key or an unseated pack. Pop the pack out, check the contacts for ice, and click it back in until it latches.

If the machine still won't respond in deep cold, bring the pack inside for twenty minutes. A warm pack is often the entire fix. The ignition logic here is simple on and off, much like a push-button start on a car, so there's little to diagnose beyond power delivery.

Special Conditions: Deep Cold and the Warm Restart

Two situations break the standard sequence: starting below 20°F, and restarting an engine that's already hot. Both need adjustments, and they pull in opposite directions.

Starting Below 20°F: Choke Behavior, Fuel Choice, and Battery Warmth

Cold air is dense, fuel atomizes poorly, and oil is thick. The engine needs more fuel and less cranking resistance.

If you have electric start, use it. Save your shoulder for the snow. Crank in five-second bursts with ten-second gaps so the starter motor doesn't overheat.

On the fuel side, fresh winter-blend gasoline vaporizes better than summer gas, and ethanol-free fuel avoids the moisture uptake that plagues cold tanks. For four-cycle engines, manufacturer specs typically call for 5W-30 synthetic in winter, which cranks easier than a heavier oil.

Store the machine where it stays above freezing if you can. A heated garage solves more cold-start problems than any additive.

Restarting a Warm Engine After a Stall Mid-Driveway

A warm engine needs no choke and no prime. Those two things are exactly what flood it.

Set the throttle to fast and pull, or press the button. It should catch in one or two attempts.

If it doesn't, you've likely flooded it already. Push the throttle to full and pull several times with the choke fully off. That wide-open throttle lets extra air through and clears the rich mixture.

Then start normally.

Warm restarts also reveal mechanical faults. An engine that dies under load when hot is often starving for fuel or overheating, and no amount of choke technique will fix that.

Troubleshooting: When It Still Won't Start

Every engine needs four things: fuel, spark, air, and compression. If a machine won't start, one of those is missing. Work through them in that order.

Sat All Summer: Stale Fuel and the Varnished Carburetor

Drain the tank and the float bowl before you do anything else. If the fuel smells like paint thinner, it's done.

Fill with fresh gas, add a dose of carb cleaner to the tank, and try again. If it still won't fire, the idle jet is blocked and no additive will clear it. The carburetor comes off, gets cleaned, and often gets a rebuild kit.

Flooded Engine from Over-Priming (and How to Clear It)

Pull the spark plug. If the electrode is wet, you've found your problem.

Dry the plug, crank the engine twice with the plug out and the ignition off to blow the excess fuel out, then refit. Restart with no choke and no prime.

Resist the shortcut of a shot of starting ether to get it going. It can light a stubborn engine, but it washes oil off the cylinder walls and masks the real fault.

Electric Start That Won't Crank: Outlets, Cords, GFCI, and the Starter Motor

Check these in order and you'll find it fast:

• Is the outlet live? Test it with a lamp.
• Is the GFCI tripped? Reset it at the receptacle.
• Is the cord the right gauge? A long 14-gauge run in cold sags badly.
• Is the key on and the fuel valve open?
• Are the starter terminals clean and tight?

If all five pass and the starter is silent, the starter motor or its solenoid has failed. That's a replaceable part, not a dead machine.

Pull Cord That Snaps Back, Sticks, or Feels Locked

A cord that rips back into the housing signals a broken recoil spring or a compression release that isn't working. A cord that won't move at all points to hydro-lock or a frozen auger.

Pull the spark plug and try again. If the cord moves freely with the plug out, fuel was pooling on the piston. Dry the cylinder, refit the plug, and start with the choke off.

The Starting Mistakes That Flood Engines and Seize Pistons

Most no-start situations are self-inflicted. These are the ones we see over and over.

• Priming a warm engine. Extra fuel on a hot intake floods it instantly.
• Holding full choke after the engine catches. Fuel load climbs, the plug fouls, the engine dies.
• Straight gas in a two-cycle. The piston scores in minutes.
• Using last season's mix. Oil settles, fuel loses volatility, the engine runs lean.
• Starting indoors "just to warm it up." Carbon monoxide has no smell and no early warning.
• Pulling the cord with the key off. Twenty pulls later, you decide the machine is broken.
• Leaving the fuel valve closed. The engine runs for twenty seconds, then dies on the driveway.
• Tipping the machine to inspect the auger. Oil migrates into the cylinder and causes a hydraulic lock.
• Storing it full of untreated ethanol fuel. That's the varnished carburetor you'll meet in December.
• Running over the extension cord. A nicked cord plus a wet driveway is a shock hazard.
• Loading the auger on a cold engine. Give it 30 to 60 seconds of idle first.
• Running the machine unattended near kids or pets. The auger doesn't stop for anything.

Every one of these costs less to prevent than to repair. A fuel stabilizer, a spare plug, and a two-minute checklist handle most of them.

Safety Non-Negotiables: Carbon Monoxide, the Auger, and the Discharge Chute

Getting the engine to fire is the technical half of this job. This section is the half that keeps you whole. Both hazards below are common, both are quiet, and both are beaten by habits that cost you nothing.

Carbon Monoxide: Why an Open Garage Door Doesn't Help

Carbon monoxide binds to your red blood cells roughly two hundred times more readily than oxygen does. Once it's attached, those cells stop carrying oxygen. Your body keeps running on a shrinking supply, and the early symptoms are easy to dismiss: a headache, mild dizziness, some nausea.

An open overhead door doesn't make the space safe. The draft stirs exhaust around as much as it clears it. In an attached garage, the gas also migrates through shared walls and door seals into the house.

"Just a minute to warm it up" is still minutes of buildup in a box.

You've already seen the rule once in this article. Here's the why behind it. The machine starts on the driveway, in any weather, at any hour.

If you ever feel off while one is running, shut it down and get to open air. Those symptoms are the only warning you get.

The Clogged Chute: Where Snowblower Injuries Actually Happen

Injury data from the Consumer Product Safety Commission tells one consistent story. Emergency rooms see thousands of snow thrower injuries each season, and the dominant pattern is a hand reaching into a clogged discharge chute. It's rarely an engine screaming at full throttle.

It's an idling engine, a stalled one, or a belt that's still under tension.

The trap unfolds the same way every time. Wet snow bridges the chute and the engine bogs down or stalls. The auger control is still latched, or the drive belt is still loaded.

You reach in to pull the clog free, and then the belt grabs, or the tension releases as the blockage shifts. Either way, the auger wins.

The safe sequence has no shortcuts:

1. Shut the engine off.
2. Remove the key.
3. Release every control lever.
4. Wait until all movement stops, belt included.
5. Clear the blockage with the cleanout tool stowed on the housing.

That cleanout tool exists because fingers don't grow back. Keep it where it lives on the machine, not in a drawer.

One more thing to undo if you find it on a used machine. Some owners zip-tie or wedge the auger lever closed so they don't have to hold it. That lever is a deadman switch, and it's the only brake between your hand and the blades.

The Rest of the Safety Checklist

• No scarves, drawstrings, hoodie cords, or loose cuffs. An auger that catches fabric pulls the attached arm with it.
• Refuel with the engine off and cooled down. Gasoline hitting a hot muffler ignites.
• Fill outdoors, wipe spills, and store fuel in an approved container away from ignition sources.
• Keep cord connections out of the snow and never drive the machine over a live cord.
• Aim the chute away from the road, cars, windows, and anyone nearby. Ice chunks and gravel leave the chute at speed.
• Keep kids and pets indoors or well behind the machine. Never step away from one that's running.
• Wear hearing protection on gas units. Operator-position noise typically runs high 80s to mid 90s decibels, past the level where NIOSH recommends protection.
• Add eye protection. The chute throws more than snow.
• On slopes, work up and down, not across the face. A wheel-drive machine on a sidehill drags you downhill.

Off-Season Prep That Makes Next Winter's First Start a One-Pull

A one-pull December start gets decided in April and confirmed in October. What you do at the last shutdown, and again on the first dry Saturday of fall, does more for starting than any choke technique ever will.

The Spring Shutdown: Ten Minutes That Decide December

1. Handle the fuel with a plan. Run the tank and float bowl dry, or fill the tank completely with stabilized fuel. The one option that's always wrong is a half tank of untreated ethanol blend sitting until Thanksgiving.
2. Change the oil on a four-cycle now. Combustion acids and condensation sit in the crankcase all summer and etch bearings.
3. Pull the spark plug, pour a teaspoon of engine oil into the cylinder, and pull the cord once slowly to spread it. Refit the plug.
4. Grease the auger shaft and chute pivots per the manual.
5. Scrape the salt and grime off the housing. Salt accelerates rust on every bare surface.
6. Inspect belts, shear pins, and skid shoes. Replace what's marginal while parts are still in stock.
7. Store the machine dry, covered, and off a damp concrete floor.
8. Bring batterypack indoors and store it at 40 to 60 percent charge, out of the cold.

That last step matters more than it looks. A lithium pack left dead or left at 100 percent through a hot summer loses capacity permanently. Come December you'll blame the machine for a battery that aged on a shelf.

The Fall Wake-Up: What to Do Before the First Storm

Don't wait for the forecast to turn. Pick a dry Saturday in late September or early October and run the machine.

• Pull the cord or press the starter. It should fire within two attempts after a summer of sitting.
• Let it run for five minutes. Listen for surging, which points to a partly blocked jet.
• Engage the auger and the drive briefly. Confirm both respond and nothing squeals.
• Check tire pressure. Pneumatic tires lose a few psi a month and a soft tire kills traction.
• Verify the headlight, heated grips, and electric chute controls.
• Recheck the shear pins. A missing one from last March is a spring surprise.

A machine that runs cleanly in October almost always runs cleanly in January. One that coughs in October is telling you the carburetor needs attention while the shops are empty.

Fuel Storage That Survives Eight Months

Stabilizer works, but it's not magic. Dose it at the pump, run the engine a few minutes so treated fuel reaches the carburetor, and then decide between two clean options.

Ethanol-free fuel is worth the extra cost for any machine that sits. It doesn't absorb moisture the way E10 does, and it doesn't leave the same varnish behind. If you can only get E10, dose it with stabilizer the day you buy it, not the day you store it.

Long-Term Care That Keeps the Starter Alive

The recoil assembly is the part most likely to fail from neglect. Its spring and rope sit under tension and dry grease. A few drops of light oil on the rope guide each fall keeps the pull smooth.

Electric starters fail from corrosion, not wear. Clean the terminals, keep the plug cap dry, and store the cord indoors. The starter motor itself usually outlives the machine.

Belts deserve a look too. A drive belt that's been sitting in one position develops a set, and a set belt slips under load. Spin the auger by hand with the engine off and watch the belt track.

If it wobbles or looks glazed, replace it before the season.

Quick-Reference Decision Guide: Find Your Starting Path in One Table

Everything above, boiled down to a lookup. Find your machine, follow the row.

Three rules cover the whole table. Match the fuel to the engine, match the choke to the engine temperature, and match the start method to what's on the machine. Everything else is detail.

If you're still stuck after one honest pass through the branches, stop pulling. Twenty minutes of diagnosis beats an hour of cranking, and a flooded engine plus a drained battery is a worse problem than the one you started with.

Frequently Asked Questions

How many times should I press the primer bulb?

Three firm presses is the standard figure for a cold engine, and zero once it's warm. Manufacturer manuals vary between two and five, so check yours. More than that floods the intake, and a flooded engine usually needs the plug pulled and dried before it will fire.

Why does my snowblower start and then die right away?

The choke came off too soon, or fuel isn't flowing steadily. Hold half choke for fifteen to thirty seconds after it catches. If it still dies, check the fuel valve, the tank level, and whether last season's fuel is still in the bowl.

A partly blocked idle jet produces exactly this symptom.

Can I start my snowblower in the garage if the door is open?

No. Carbon monoxide builds faster than an open door clears it, and it migrates into the house through shared walls. Start and run the machine on the driveway, even in a storm, even for half a minute.

There is no safe enclosed-space version of this.

How do I start a snowblower that sat all summer?

Drain the old fuel from the tank and float bowl first. Refill with fresh gas, or fresh 50:1 mix on a two-cycle. Set full choke and start normally.

If it won't fire, the carburetor jets are varnished and need cleaning, since no additive will dissolve what's already hardened.

Do I use the choke on a warm engine?

No. A warm engine needs no choke and no prime, and either one floods it. Set the throttle to fast and pull or press the button.

If it's already flooded from a choke attempt, hold the throttle wide open and crank with the choke off to clear the excess fuel.

What kind of gas does a snowblower take, and does it need oil mixed in?

Four-cycle engines take straight gasoline, 87 octane or higher, with oil living separately in the crankcase. Two-cycle engines need gasoline mixed with two-cycle oil, usually at 50:1, which is 2.6 ounces of oil per gallon. Check the fuel cap sticker before you fill, because the wrong answer costs a piston.