Will A Snowblower Start With Old Gas?

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 the more likely outcome. Draining the gas and refueling often solves the problem, but a full carburetor cleaning may be needed also. Adding a fuel stabilizer at 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 happening again next season. I’ll also cover cleaning the carburetor bowl.

Mower gas cap

Vented Gas Cap

Diagnosing Snowblower 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. Problem is, ethanol attracts moisture and moisture in the fuel system causes corrosion. In addition, an open fuel system allows gas to evaporate, 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 later).

Ok so now you know why the gas goes stale, now let’s confirm our suspicions. There are a couple of ways to check 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 attractive gasoline aroma and becomes more acidic, (yes we are still talking about gas). 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 turns yellow. (pee color)

Mower gas tank

Winged & Threaded caps

Removing Old Gas From Snowblower

There are two ways to remove old gas from a snowblower fuel system. engine. Drain it out or syphon it. In the workshop I use an oil and gas syphon to remove the gas from the gas tank. It’s fast, easy, mess free and safe. You can check out the syphon I use here on the “Snowblower maintenance tools”.

The syphon won’t drain the system completely, the carburetor and fuel lines still hold stale gas. Removing the carburetor bowl drain, or removing the carburetor gas bowl altogether drains the remaining fuel.

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.

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!

To drain the gas bowl, follow these steps:

  • Park snowblower outdoors or in well ventilated area
  • Use suitable low profile container & have some rags handy
  • Remove gas tank cap
  • Remove carburetor gas bowl drain bolt or remove gas bowl
Vented mower gas caps

Vented gas caps

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 complete.

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”.

Adding 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.

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 the 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 the 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 gas stabilizer in all your small engine kit, including 2 cycle engines (not a substitute for oil mix). It works great in classic cars, ATV’s, boats, mowers, chainsaws, weed eaters, leaf blowers, generators etc.


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.