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Will Snowblower Start With Old Gas? Mechanic weighs in

By: Author John Cunningham. Published: 2021/06/14 at 10:00 am

Cranking and cranking and nothing, what a pain in the ass. You are correct to suspect stale gas; it is the most common cause of a no-start after a period of storage. But don’t panic; I’ll bet we can get this figured out right now.

A snowblower may start with old gas in the system. However, a no-start is a more likely outcome. Draining the gas and refueling often solves the problem, but a full carburetor cleaning may also be needed. Adding a fuel stabilizer at the season’s end will prevent stale gas and carburetor gumming.

In this post, you’ll learn how to diagnose stale gas, you’ll learn a mess-free way to remove the old gas, and you’ll learn how to prevent this from happening again next season. I’ll also cover cleaning the carburetor bowl.

Stale Gas

Stale gas is a common problem, and increasingly so as blended gasoline, also known as ethanol, has become the gas of choice. Your snowblower may start with old gas in the system, but a no-start is more common. Modern gas goes stale quickly, and ethanol goes stale much faster than straight gas.

In an open fuel system (all small engines), gas begins to go stale after just one month.

Snowblower employs an open fuel system, meaning the system is open to the atmosphere. The problem is ethanol attracts moisture, and moisture in the fuel system causes corrosion. In addition, an open fuel system allows gas to evaporate, and the remaining chemicals gum up the carburetor.

These problems don’t present in cars or trucks as they run sealed gas systems but do present in older classic cars. If all that isn’t bad enough, ethanol also damages the rubber and plastic components of the fuel system. But it’s not all bad news; there is a solution, and it’s easy and inexpensive to implement.


It’s called a gas stabilizer (more on this below).

Need more info on the fuel system, carburetor components, and how they work, you can check them out here.

Small engine carburetor components

Diagnosing Snowblower Stale Gas

Ok, so now you know why the gas goes stale, now let’s confirm our suspicions. There are a couple of ways to check the gas quality, by smell and look.

Checking gas comes easily to me as I’m working with it in the workshop all the time. I can usually tell if gas is stale by the smell. Stale gas loses that gasoline aroma and becomes more acidic.

Tank drain

I’m not suggesting you sniff the gas, but instead, take a sample of gas and place it in a glass jam jar; the color tells the tale. (To remove a gas sample, see removing old gas below). Fresh gas is clear and stale gas is yellow.

Removing Old Gas From Snowblower

There are two ways to remove old gas from a snowblower fuel system. Drain it out or siphon it. In the workshop, I use an oil and gas siphon to remove the gas from the gas tank. It’s fast, easy, mess-free, and safe.

You can check out the siphon I use here on the “Snowblower maintenance tools” or check out the Amazon link below.

Amazon Gas and Oil Siphon

Before working on the fuel system, you’ll need to work in a well-ventilated area; you’ll need gloves and eye protection. Gas in the eyes stings a lot!

Syphon old gas

The siphon won’t drain the system completely; the carburetor and fuel lines still hold some stale gas.

Removing the carburetor bowl drain or removing the carburetor gas bowl altogether drains the remaining fuel. (see below)

Gas Line – If your gas tank is pretty full, draining it off through the open gas bowl is possible, but it’s messy and awkward. Instead, remove the gas line from the carburetor and feed the pipe into a suitable container to drain the tank.

But your gas bowl and lines still contain stale gas, so you’ll need to drain the gas bowl, also. (see below)

Gas tank draining
Gas line off

Removing Gas Line – In order to remove the gas line, you’ll need to remove the carburetor housing covers. You’ll need pliers to slide the gas clamp and remove the gas line.

To drain the gas bowl, follow these steps:

  • Park the snowblower outdoors or in a well-ventilated area
  • Use a suitable low-profile container & have some rags handy
  • Remove the gas tank cap
carb covers

Access – Remove covers to access the carburetor

Remove Drain Bolt – Remove the drain, but have a container and some rags at the ready to catch and soak up the spill.

Bowl drain
Fit bowl

No Drain Bolt – Some bowls won’t have a drain fitted; in those cases, you’ll need to remove the bowl altogether. When refitting, avoid pinching the seal and overtightening.

Rinse – When completely drained, add fresh gas to rinse the system before refitting the drain bolt.

Bowl drain

Cleaning Snowblower Carburetor Bowl

With the gas bowl removed, clean the bowl using a clean rag. Check for corrosion. A little won’t hurt, but a lot of corrosion inside the bowl will cause you lots of ongoing poor running issues like surging, stalling, and lack of power. If just the bowl is affected, it can be replaced; if not, replace the carburetor completely.

Use a good quality carburetor cleaner and spray the bowl. Check out the cleaner I use here on the “Snowblower maintenance tools.” Using the cleaner straw to direct the cleaner into the fuel jet and emulsion tube. A badly corroded or gummed gas bowl will mean the jet and emulsion tube are blocked or partially blocked and will need cleaning.

I’ve covered carburetor cleaning previously, and you can check it out here “Carburetor cleaning” or check out the video here. (It’s a mower carburetor, but they’re all similar).

Carburetor gas bowl cleaning

Gas Stabilizer

Gas stabilizer, as said earlier, is the antidote to ethanol and an open fuel system. It’s inexpensive, easy to use, and will save you a bunch of money come snow season. The gas stabilizer is a fuel additive, and it may be used all season. However, it’s only necessary when the blower is going into storage.

You can check out the stabilizer I recommend here on the “Snowblower maintenance tools.”

Mixing Gas Stabilizer

Mix as prescribed. The brand I use (Sta-Bil) recommends a half-ounce (tablespoon) to one gallon of gas, easy! The measure on the container makes for accurate and simple execution. Empty the measure into a gallon of fresh gas and shake it to mix.

Adding Gas Stabilizer

Add the mixed gas to a low gas tank; you’ll need to run the snowblower engine for 5 minutes to ensure the mixture makes its way to the carburetor.

It’s as easy as that; your fuel system is protected from gumming and stale gas for up to two years. You can use a gas stabilizer in all your small engine kit, including 2-cycle engines (not a substitute for oil mix). It works great in classic cars, ATVs, boats, mowers, chainsaws, weed eaters, leaf blowers, generators, etc.

Adding Gas Stabilizer – It’s all covered here in this video, “Adding gas stabilizer.”

Gas stabilizer