Starting Fluid

What Is Starting Fluid and Why It Matters

Starting fluid is a volatile, flammable liquid which is used to aid the starting of internal combustion engines, especially during cold weather or in engines that are difficult to start using conventional starting procedures. It is typically available in an aerosol spray can, and may sometimes be used for starting direct injected diesel engines or lean burn spark engines running on alcohol fuel. Whether you're trying to fire up a snow blower on a frigid morning, coax life into a stored lawn mower, or get a stubborn diesel engine running, starting fluid can be an invaluable diagnostic and cold-start tool.

Some modern starting fluid products contain mostly volatile hydrocarbons such as heptane (the main component of natural gasoline), with a small portion of diethyl ether, and carbon dioxide (as a propellant). The magic of starting fluid lies in its chemistry: diethyl ether quickly vaporizes, creating an easily ignitable fuel-air mixture within the engine's cylinders. This makes ignition possible even when normal fuel won't readily vaporize in cold temperatures or when compression and spark conditions are less than ideal.

When and How to Use Starting Fluid

Starting fluid is sprayed into the engine intake near the air filter, or into the carburetor bore or a spark plug hole of an engine to get added fuel to the combustion cylinder quickly. Using starting fluid to get the engine running faster avoids wear to starters and fatigue to one's arm with pull start engines, especially on rarely used machines. It's particularly valuable for cold weather starting, vehicles that have run out of fuel and need time to restore fuel pressure, and sometimes with flooded engines.

It can be used as a diagnostic tool as well. If your machine's engine does not start, and starting fluid helps it start momentarily before quitting, you know that the engine isn't getting its proper fuel delivery and it's likely the carburetor may need to be cleaned and/or rebuilt. However, it's important to use starting fluid sparingly and as intended. If you have to use starting fluid, use it sparingly. If a couple short bursts into the intake don't elicit a cough or two from the engine, emptying the can isn't going to work, either.

Important Precautions and Considerations

While starting fluid is highly effective when used correctly, it requires careful handling. Caution is required when using starting fluid with diesel engines that have preheat systems in the intake or glow-plugs installed, as the starting fluid may pre-ignite, leading to engine damage. Additionally, starting fluid is not recommended for regular use with some two-stroke engines because it does not possess lubricating qualities by itself. Lubrication for two-stroke engines is achieved using oil that is either mixed into the fuel by the user or injected automatically into the fuel supply.

Modern formulations have addressed some of these concerns. Many quality starting fluid products now include upper cylinder lubricants and corrosion inhibitors to protect engine components during cold starts. The key is understanding that starting fluid should be a temporary diagnostic aid or occasional cold-weather helper, not a regular starting solution. If an engine consistently requires starting fluid, there's likely an underlying issue with the fuel system, ignition, or compression that needs professional attention.

Top Starting Fluid Brands

When selecting starting fluid, quality matters for engine protection and reliability. Golden Eagle Manufacturing offers starting fluid solutions that meet the demands of performance-minded users who need dependable cold-start assistance. Meanwhile, CRC Industries has built a strong reputation in the chemical solutions market with their Jump Start line, featuring formulations that include upper cylinder lubricants to minimize wear during cold starts and remain effective in temperatures down to -65°F.

Whether you're maintaining lawn equipment, servicing marine engines, troubleshooting automotive starting problems, or preparing equipment for winter storage and spring startup, the right starting fluid ensures you're ready when challenging conditions strike. Keep a can on hand for those moments when conventional starting methods fall short, but always remember to address the root cause of persistent starting difficulties.