Snowblower Not Starting After Summer

That time of year again, seems like no time ago since I put the snowblower away. Problems often arise at the start of the season. I’m a mechanic and my customers usually say something like, “It was running fine when I put it away”, sound familiar?

A snowblower that won’t start after summer storage likely suffers from fuel system contamination. Draining the fuel system and refueling usually solves the issue, however a carburetor cleaning may also be required.

In this post you’ll learn the likely reason why your snowblower won’t start and you’ll also learn what you can do to fix it right now.

Mower gas cap

Vented Gas Cap

Common Causes Of No Start After Summer Storage

The single most common cause of no starts after summer storage is as you know, fuel system contamination. But what does that mean? you might ask.

It means the gas in your snowblower has gone stale and in severe cases the stale gas congeals and gums up the fuel system, clogging the carburetor.

Stale gas is a simple repair, but gumming of the carburetor requires a little more work, but I’ve got you covered, we’ll deal with both later in this post

All that said, stale gas, although the most likely cause, it isn’t the only possible cause. Here’s a short list of other possibles based on my experience, together with what you’ll need to de to repair them:

  • Fouled spark plug – remove, clean and gap or replace.
  • Faulty armature (coil) – armature produces voltage to fire the plug, it lives under the engine cover. If a known good plug does not produce a spark and the on/off control switch is good, then go ahead and replace the armature, it’s faulty.
  • Stuck open valve – commonly happens after an engine lays up for s time. If the valve is open after shut down corrosion can form on the stem and prevent it from closing fully. Remove the cam cover and free it by pushing on the valve spring. (see storage prep below to combat sticking valves)
Mower gas tank

Winged & Threaded caps

Fuel System Diagnosis

Ok, so we suspect the problem is fuel contamination. Checking is pretty simple, in the workshop to quickly discover if I’m dealing with a fuel system issue or a spark issue I pour some fresh gas down the carburetor.

I attempt to start the engine in the regular way and if the engine starts or makes a good attempt to start, I know the fuel is the issue. If on the other hand there is no change in the engine’s behavior, I’ll suspect one of the less common faults listed above.

Vented mower gas caps

Vented gas caps

But if you don’t fancy running that test, it’s not a problem. The next test will also help confirm fuel system contamination.

Follow these steps:

  1. Turn gas tap off (if fitted) or pinch gas line gently with a clamp
  2. Locate the gas bowl at the base of the carburetor
  3. Remove the gas bowl fastener (one bolt usually)
  4. Check the bowl for grit, corrosion or cloudy looking gas

Fuel System Cleaning

Cleaning the fuel system requires draining the gas tank, cleaning or replacing the gas filter and of course cleaning the carburetor.

For many though, just draining the gas tank and cleaning the gas bowl is enough to fix the issue.

I’ve covered carburetor cleaning in this post, it’s a mower carburetor, but it’s an identical process – “Mower carburetor cleaning”.

Storing A Snowblower Like a Pro

Storing the snowblower correctly will ensure your machine starts next season first crank. Storage preparation isn’t difficult and only takes about an hour of your time. You may need to buy a few items to nail this procedure. You can find all the products you’ll need here on the “Snowblower maintenance tools page”.

Use gas stabilizer

Gas stabilizer keeps gas fresh over the storage period. This is top of the list for good reason. Blended gas, known as ethanol, goes stale quickly. When it goes stale it can congeal inside the carburetor causing damage.

In addition to going stale, ethanol damages the plastic and rubber components of the fuel system. To protect your snowblower fuel system, add gas stabilizer.

Close valves

Valves open and close to allow gas in and exhaust gases out. After shut down, it’s normal for a valve to remain open. This isn’t an issue for short term storage, but over the longer term, corrosion can enter the cylinder through the open valve.

To prevent this, add some engine oil and we’ll place the engine at TDC.

To close the valve go ahead and:

  • Remove spark plug
  • Add capful of engine oil to cylinder
  • Place non metallic blunt object inside the cylinder (pencil)
  • Turn over engine by hand until the pencil is pushed to the top of the cylinder (valves are now closed)
  • Refit the spark plug

Clean body & protect

Wash the machine thoroughly, allow dry and coat with Dupont coating. The Teflon coat helps guard against moisture, rust, and electrical damage. You can use WD40 but the Teflon works best. Safe to spray everything but belts.

Using a breathable cover

Many people place a simple plastic sheet over the machine, this isn’t ideal. Plastic will trap moisture in and that’s almost as bad as the machine sitting in the rain. A good quality breathable cover will allow trapped moisture to escape through the material.

You can check out the cover I recommend here on the “Snowblower maintenance tools page”

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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.