No, you should not put lawn mower gas in your car. While it might seem like a quick fix in a pinch, using fuel formulated for small engines in a modern car can cause significant and expensive damage. The primary risks involve the fuel's ethanol content and its lack of essential detergents. Lawn mower fuel is often ethanol-free, which is good for small engines that sit idle for long periods, but modern car engines are designed to run on fuel containing up to 10% ethanol (E10). More critically, gasoline for automobiles contains a specific package of detergents that prevent carbon deposits from building up on fuel injectors and intake valves. Without these detergents, your car's engine performance and fuel efficiency will suffer over time.
The octane rating is another factor. Most lawn mower fuel is 87 octane, which matches regular gasoline. However, if your car requires premium fuel (91 octane or higher), using 87 octane lawn mower gas could lead to engine knocking and potential damage. The safest rule is to always use the grade of gasoline recommended in your owner's manual, purchased from a reputable gas station. This ensures the fuel has the correct additives to keep your engine clean and running smoothly.
| Fuel Characteristic | Typical Lawn Mower Gas | Standard Automobile Gas (E10) | Risk to Car |
|---|
| Ethanol Content | Often 0% (Ethanol-Free) | Up to 10% | Potential damage to seals and fuel system components not designed for pure gasoline. |
| Detergent Additives | Minimal or None | Yes (Top Tier Detergents) | High risk of carbon deposits on fuel injectors and valves, reducing performance. |
| Octane Rating | Usually 87 | 87, 89, 91+ | Risk of engine knocking if car requires premium fuel. |
| Stabilizers | Often included for storage | Not typically a focus | Not directly harmful, but unnecessary for daily-driven vehicles. |
In summary, the convenience of using a can of lawn mower gas is far outweighed by the risk of costly repairs. It's a gamble that's not worth taking with your vehicle's engine.
