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Snowblower Won’t Start After Carburetor Cleaning – Fixed!

No start after carb clean – soooo frustrating; JUST START ALREADY! All carburetors need cleaning at some stage, so you made the right call, and I’ll bet it’s something simple causing the no-start, something we can fix right now. I’m a mechanic with 20-plus years of experience, and you are in the right place.

Gas tank contamination is a common reason why a snowblower won’t start after a carburetor cleaning. When cleaning a carburetor, it’s best practice to drain and clean the gas tank and refill it with fresh gas before starting the engine. Other common reasons include:

  • Dirty carburetor
  • Intake gasket leaks
  • Fuel starvation
  • Linkages incorrectly positioned
  • Primer fault
  • Coke fault

In this post, we’ll cover the reasons why you have a no-start snowblower after carburetor cleaning, but before we begin troubleshooting, we’ll check the basics first.

Check the Basics First

It’s easy to overlook something simple when you are in the thick of battle, and that’s what this section is all about. Here, we’ll cover all the simple stuff that under fire we often forget; let’s just check these off quickly before moving on to troubleshooting proper.

Check that your gas is fresh and the plug wire is on securely. Go ahead and check the following stating procedure:

Snow blower Starting sequence
  1. Ignition On?
  2. Gas valve On?
  3. Throttle set to high?
  4. Choke On
  5. Primer bulb pressed
  6. Pull to start

I’m making an assumption here that your snowblower ran prior to carburetor cleaning, but if I’ve got that wrong, then you could be dealing with an issue other than a carburetor. If that is the case, you may find the links below helpful:

If, however, your snowblower ran prior to carb cleaning and now doesn’t, keep reading. We’re about to remove the pebble.

Carburetor Troubleshooting

There are, as you can imagine, several opportunities to get carburetor cleaning wrong, and even more when you add rebuilding and refitting the carburetor.

But that’s Okay, don’t sweat it; we’ll get it figured out by running a few diagnostic tests, but first, let’s look at the likely carburetor-related reasons for a no-start.

Likely No-Start Causes After Carburetor Rebuild

  • Contaminated gas
  • Dirty carburetor
  • Intake gasket leaks
  • Fuel starvation
  • Linkages incorrectly positioned
  • Primer fault
  • Coke fault

It is worth noting that small engine equipment can be awkward to work on, and we often place them in positions to suit us and the job at hand. The trouble with that is it can cause oil and gas to get into places it shouldn’t, which sometimes results in flooding and fouling of the spark plug.

Oily plug

As this is a somewhat common issue, and although not directly carburetor related, nonetheless, I think it is worth checking the spark plug condition and might as well check the spark too.

I’ve covered both previously, and you can check that out right here – How often to replace snowblower spark plug?

Assuming all checks out Okay with the plug, let’s now look at our likely common causes one by one in a little more detail.

Contaminated gas

Contaminated gas causes a ton of issues with all types of small engine kit. Likely that’s why you had to clean the carburetor in the first place.

Gummed-carburetor

Blended gas (pretty much all gas today) tends to go stale quickly, especially in small engine kit that lie idle for a time (all small engine kit).

In my experience, when folks clean their carburetor, they often forget to drain and clean the gas tank; you can see where I’m going with this. Yep, the stale gas has contaminated the carburetor again.

Contaminating a clean carburetor and clean gas tank with contaminated gas in a storage gas can is also popular.

So, either of these sounds like your issue; drain the gas from the gas tank, and you’ll only need to drain the carburetor gas bowl (no need to remove the carburetor again for cleaning).

Here are a couple of links to help you out with that:

After cleaning both the tank and bowl, consider using a gas stabilizer to help prevent carburetor gumming and other fuel-related issues associated with blended gas. Check out how to mix and add gas stabilizer right here – Fuel stabilizer mixing & adding

Dirty carburetor

Carburetors won’t tolerate dirt; they are so finely calibrated that even a grain of crap caught in the wrong spot will cause a no-start – I’m not kidding. Real care is needed when cleaning a carb; I’m not saying you messed this up. I’m just saying a dirty carb is still high on our list of reasons it won’t start.

In particular, many snowblower carburetors are fitted with a carburetor bowl fastener with an integrated fuel jet. These carburetors are famous for clogging up and causing no-starts or running issues.

Fuel feed jet

If you have this carburetor bowl fastener/jet style, it may be worth removing and checking that the jet is perfectly clean.

Mechanics tip – I use a wire brush strand to probe the center drilling.

Intake gasket leaks

Intake and carburetor gaskets are critical for proper air-to-fuel ratios. The gaskets are sandwiched between the carburetor and the engine, making an airtight seal. Your carburetor is a finely balanced bit of kit, it has several functions, but its main one is to add just the right amount of gas to the volume of air that passes through it.

As it’s a mechanical component, it doesn’t measure airflow. Instead, it uses the venturi effect and vacuum to suck fuel from the fuel bowl through tiny jets and fuel passages in the carburetor body.

LMF-Fuel-ratio

The jets are calibrated at the factory to add one part gas for every 14.7 parts air (oxygen) that passes through it.

Any disruption of the air-to-fuel ratio causes immediate performance issues. Imagine a failure in our carburetor gasket located just after the carburetor, say at the manifold. This type of failure we call a vacuum leak.

And a vacuum leak allows unmetered air (which hasn’t passed through the carburetor) into the engine. The effects are varied depending on how bad the leak is, but if big enough, it will prevent the engine from starting.

It is worth noting that many gaskets have a side designed to face the engine, meaning switching them the other way may block up vital passageways.

Search Google images for your make and model to ensure the gaskets are orientated correctly.

Fuel starvation

Fuel starvation is as it sounds; it’s a lack of gas where it’s needed – inside the combustion chamber. Starvation may be caused for lots of reasons; here are the most common ones:

Gas shot

A fast way to diagnose fuel starvation is to run a shot of gas into the engine and attempt to start it; what the engine does or doesn’t do next determines where we test next.

I use this test a lot; you can check it out here – Gas shot test

Fuel starvation diagnosis is straightforward, and I’ve covered this topic recently; you can check it out right here – Snowblower starts then dies.

Linkages incorrectly positioned

Snowblowers use throttle linkage and return springs to control the throttle. The lever typically is part of the governor, an internal engine component to help prevent the engine from overrevving and imploding.

The rod and springs aren’t very complex, but they can be delicate, check that the throttle operates freely and the spring return is functional.

Throttle links

Throttle governor and return spring

Primer fault

A primer bulb is needed for quick starts, but in theory, cranking the engine with just the choke applied should start the engine; it just might crank for a little longer than normal before it fires up. A faulty primer bulb could cause a no-start if it’s cold enough.

Primer bulbs are simple; it’s a rubber bulb and some rubber hose; pressing the bulb injects extra gas into the carburetor.

A quick inspection will reveal issues.

Primer-bulb-hose-pipe

Typical issues include:

  • Perished rubber
  • Tears or pierced bulb
  • Disconnected hose

Coke fault

As snowblowers work in cold conditions, the choke is critical; no choke means no start. Choke, as you know, enriches the air-to-fuel mixture; it does so by employing a plate that the operator manually rotates to restrict inflow through the carburetor.

Carb-choke-on

Snowblower choke systems are usually really simple, so choke is at the end of our list.

But since you are still reading and not moving snow, we’d best check it. Checking the choke system is something I have covered previously, and you can check it out here – Check snowblower choke system.

Carburetor Cleaning

Carburetor cleaning is one of those jobs we don’t do very often, so we may be a little foggy on the subject. Check out the link below, where I walk you through the process.

Summary

Gas tank contamination is a common cause of a no-start situation after carburetor cleaning. Check the basics first, check things like fresh gas, gas valve on, ignition on, choke on, throttle on, primer bulb used, and the spark plug wire in place before moving on to troubleshooting the carburetor itself.

Other likely causes for a no-start after carburetor cleaning are contaminated gas, dirty carburetor, intake gasket leaks, fuel starvation, incorrectly positioned linkages, primer, and choke.

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