Imagine that you are about to get your classic vehicle out of storage, or you have just found the perfect barn find. If it has a carburetor, and has sat for a while, it may have trouble starting.  If it’s cold outside, again it may have trouble starting. Starting fluid is the quick fix to start something.  But could you damage your fuel system or engine by using it?

Is Starting Fluid Good or Bad?

If you ask five different professionals if they recommend the use of start fluid, you’ll get five different answers.  The simple answer is that it can be beneficial under certain circumstances.  But it but shouldn’t be a long-term solution to continually starting your vehicle.

When is Starting Fluid OK to Use?

Car Engine

The two most common uses for starting fluid are:

  • when it’s very cold and gasoline doesn’t want to vaporize, and
  • when you’re bringing a vehicle or engine out of storage.

In colder weather, a vehicle with a carburetor will struggle to start.  The carburetor uses internal jetting to vaporize fuel from a liquid state to a gas state.  Colder gasoline is harder to vaporize.  A vehicle with fuel injection will not have the same issue for vaporization.  This is because higher fuel pressure and fuel injectors will vaporize fuel much better.  Using starting fluid to start the engine in a cold state allows the engine to warm the gasoline as it enters the carburetor.  This helps the engine run on its own.

Likewise, starting fluid helps engines run after storage periods.  If it has a carburetor, even in warmer temperatures, it may require the engine trying to start to pump fuel from the fuel tank to the carburetor. The engine will turn over with the starter and the battery power, but that combination won’t try to start the vehicle if the battery eventually goes dead. If you have an electric fuel pump in your fuel system, you may not need a lot of starting fluid to revive your vehicle from storage.

When Should I Not Use It?

Two engines that don’t work well with starting fluid are two-strokes and diesels.  Two-stroke engines include their engine oil with the gasoline as it enters the combustion cylinder.  The engine oil included is what helps keep the engine lubricated. Starting fluid contains a portion or is completely composed of Ether. Ether is a solvent, and when mixed with oil it will dissolve and breakdown the oil. If enough starting fluid is used on a two-stroke engine, it can keep the included oil mixture from doing its job of lubricating the engine. That can score bearings and pistons and eventually lead to engine failure.

Diesel engines have high compression ratios that can ignite an Ether mixture before the engine is ready to make use of the combustion. That is called pre-ignition or detonation, and it can lead to engine damage or complete failure.

Can It Help Diagnose a Problem?

If you have to use starting fluid often, there may be a larger problem than just cold gasoline or an engine brought from storage. A clogged carburetor that needs a cleaning may prevent the engine from running well at low speeds. Your engine may also sputter a lot and refuse to run well if you have poor gasoline. You may have missed adding some AMSOIL Gasoline Stabilizer into the fuel tank before putting your vehicle in storage, and the gas has now lost its volatility. If a few squirts of starting fluid don’t allow your engine to start and run momentarily, you may have a larger problem that needs additional diagnostic work.

Starting fluid helps stubborn engine start.  But follow the directions on the container and use it cautiously. A little bit should be enough, and anything more may signal another problem. When it’s time to put your vehicle in storage, or any other equipment, take care of the engine oil and fuel system. Contact for a complete solution to store your equipment and vehicles correctly with AMSOIL oil, filters, cleaners, and stabilizers.

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