Why Your Lawn Mower Did Not Start This Spring

Updated- December, 2024

Did your lawn mower start just fine last fall, but would not start (or operated poorly) when you went to use it this spring? This is more than likely due to stale gasoline. This issue extremely common. In fact, it keeps small engine repair shops in business. There is an easy and inexpensive solution.

Stale gasoline creates gummy deposits that plug carburetors. Once that occurs, that mower is unlikely to start again without a repair.

How Quickly Does Gasoline Go Bad?

Todays’ gasoline formulas start to degrade after just 30 days. After an entire winter, small volumes of fuel will be very stale. This degradation compromises the performance characteristics of the fuel. It also promotes the formation of gummy deposits in the fuel tank, fuel lines and carburetor.

Should One Use Regular Or Premium Gasoline In Small Engines?

First, start by using premium gasoline in your small engines. Preferably premium fuel that does not have any ethanol content. Although, even premium-grade gasoline now contains ethanol in many jurisdictions. The ethanol component of gasoline can cause serious problems in small engines when it comes into contact with moisture. More on that in the description of the Quickshot product below.

Update: Ethanol Now Added To All Premium Gasoline In Canada – What to Do? 

How To Avoid Stale Gasoline

We offer two products that can play a key role in preventing stale gasoline and the resulting performance and depositing issues.

The first product is AMSOIL Gasoline Stabilizer. Gasoline stabilizer curbs oxidation in gasoline over long periods. Think of it as a preservative for gasoline. It is important to add the stabilizer product while the gasoline is relatively fresh.

We add stabilizer to every batch of fuel we bring home for lawn/garden machines and the snow-blower in winter. It is also a must for seasonal powersports machines like motorcycles, ATV, boats and snowmobiles.

AMSOIL Gasoline Stabilizer is truly a premium fuel additive. See this independent test versus Sea Foam Motor Treatment.

The second product that can prevent fuel-related problems in small engines is AMSOIL Quickshot. Quickshot is a gasoline additive for lawn/garden and powersports engines. This product provides “in-season” fuel stabilization.

Quickshot contains powerful detergents that clean fuel systems and combustion chambers.

One of the main features is that Quickshot prevents ethanol problems. When ethanol comes in contact with moisture, they attach to one another. This mixture can sink to the bottom of the fuel tank. Once this mixture is ultimately drawn into the combustion chamber, it can create a lean condition that can actually seize the engine. Quickshot neutralizes this mixture and allows it to pass through the engine with no problems. While we advocate buying premium fuel that does not contain ethanol, this may not always be available in some regions. With ethanol being so common, we also can’t depend on fuel being ethanol-free even when it is marked as such.

Can You Mix AMSOIL Gasoline Stabilizer And Quickshot?

Yes, AMSOIL Gasoline Stabilizer and Quickshot are perfectly compatible can be added to the same batch of fuel. We add both products to every fresh batch of gasoline for our lawn and garden equipment. They can be also be used in gasoline/two-stroke oil mixtures.

Conclusion

Adding a good gasoline stabilizer to every batch of fresh fuel will prevent starting problems due to degraded gasoline.

We also add AMSOIL Quickshot for cleaning power and the prevention of ethanol issues. But if you only add one product, use a good quality gasoline stabilizer.