50:1 Fuel Mix Chart – Premix Guide for 2-Stroke Engines
A 50:1 fuel-to-oil ratio is one of the most common mixtures used in two-stroke engines. Whether you’re mixing fuel for your chainsaw, dirt bike, outboard motor, or weed trimmer, getting the right ratio is crucial for engine performance and longevity. This guide explains what 50:1 means, why it’s important, and provides quick reference charts for both US gallons and metric measurements.
What Does a 50:1 Fuel Mix Mean?
A 50:1 ratio means you mix 50 parts of gasoline with 1 part of two-stroke engine oil. This ratio provides the engine with enough lubrication while minimizing carbon buildup and smoke.
For example:
- 1 gallon of gas (128 oz) mixed with 2.6 oz of oil results in a 50:1 mixture.
- 1 litre of gas requires 20 millilitres of oil.
This precise balance ensures optimal performance, especially in high-RPM tools and engines.
Why the Correct Fuel Mix Matters
Using the wrong fuel mix can:
- Damage your engine: Too little oil can cause overheating, friction, and permanent engine damage.
- Reduce performance: Improper fuel mix affects combustion, resulting in poor acceleration and engine response.
- Void your warranty: Many manufacturers specify a required fuel ratio in the owner’s manual.
Always double-check the recommended mix ratio for your specific engine, as some older models might use different ratios like 40:1 or 32:1.
To make it easier you can use the following old school reference chart.
Metric (Litres:Millilitres)
| Fuel (L) | Oil (mL) |
|---|---|
| 1 | 20 |
| 2 | 40 |
| 3 | 60 |
| 4 | 80 |
| 5 | 100 |
| 7.5 | 150 |
| 10 | 200 |
| 15 | 300 |
| 20 | 400 |
| 25 | 500 |
US (Gallons:Fluid Ounces)
| Fuel (gal) | Oil (fl oz) |
|---|---|
| 1 | 2.6 |
| 1.5 | 3.8 |
| 2 | 5.1 |
| 2.5 | 6.4 |
| 3 | 7.7 |
| 4 | 10.2 |
| 5 | 12.8 |
| 7.5 | 19.2 |
| 10 | 25.6 |
| 15 | 38.4 |
How to Mix 50:1 Fuel Properly
- Use a clean container made specifically for fuel.
- Measure the oil accurately using a graduated container or syringe.
- Add the oil first, then pour in the gasoline to aid mixing.
- Seal and shake the container well.
- Label the container with the mix ratio and date to avoid confusion.
Recommended Tools for Easy Mixing
- 2-stroke oil measuring bottle
- Premix jugs with ratio markings
- Digital fuel mix calculators or apps
2 Stroke Mix App
If you’re looking for something to help with other ratios and remind you how old your fuel is, please take a look at our app for iPhone and Apple Watch on the App Store?
Frequently Asked Questions
Q: Can I use regular motor oil?
A: No. Always use high-quality 2-stroke oil specifically designed for air-cooled engines. Regular automotive oil is not suitable.
Q: What if I accidentally use the wrong ratio?
A: If you use too much oil (e.g., 40:1 instead of 50:1), your engine may smoke more but won’t be damaged. Too little oil can cause overheating and long-term damage. Drain and remix if you’re unsure.
Q: How long does premixed fuel last?
A: Mixed fuel is best used within 30 days. Adding a fuel stabilizer can extend shelf life up to 3 months.
Common Engines That Use 50:1 Premix
- Chainsaws (Stihl, Husqvarna, Echo)
- Leaf blowers and trimmers
- Dirt bikes (KTM, Yamaha 2-strokes)
- Outboard motors (Evinrude, Mercury)
- Scooters and mopeds
Always refer to the user manual for the exact ratio.