⛵ 2-Stroke Outboard Oil Mix Calculator
Calculate the exact oil amount for any fuel volume and mix ratio — imperial & metric
| Mix Ratio | 1 US Gal (oz) | 2 US Gal (oz) | 5 US Gal (oz) | 6 US Gal (oz) | 10 US Gal (oz) |
|---|---|---|---|---|---|
| 16:1 | 8.0 oz | 16.0 oz | 40.0 oz | 48.0 oz | 80.0 oz |
| 20:1 | 6.4 oz | 12.8 oz | 32.0 oz | 38.4 oz | 64.0 oz |
| 24:1 | 5.3 oz | 10.7 oz | 26.7 oz | 32.0 oz | 53.3 oz |
| 25:1 | 5.1 oz | 10.2 oz | 25.6 oz | 30.7 oz | 51.2 oz |
| 32:1 | 4.0 oz | 8.0 oz | 20.0 oz | 24.0 oz | 40.0 oz |
| 40:1 | 3.2 oz | 6.4 oz | 16.0 oz | 19.2 oz | 32.0 oz |
| 50:1 | 2.6 oz | 5.1 oz | 12.8 oz | 15.4 oz | 25.6 oz |
| 100:1 | 1.3 oz | 2.6 oz | 6.4 oz | 7.7 oz | 12.8 oz |
| Mix Ratio | 1 Liter (ml) | 5 Liters (ml) | 10 Liters (ml) | 20 Liters (ml) | 25 Liters (ml) |
|---|---|---|---|---|---|
| 16:1 | 62.5 ml | 312 ml | 625 ml | 1250 ml | 1563 ml |
| 20:1 | 50.0 ml | 250 ml | 500 ml | 1000 ml | 1250 ml |
| 24:1 | 41.7 ml | 208 ml | 417 ml | 833 ml | 1042 ml |
| 25:1 | 40.0 ml | 200 ml | 400 ml | 800 ml | 1000 ml |
| 32:1 | 31.3 ml | 156 ml | 313 ml | 625 ml | 781 ml |
| 40:1 | 25.0 ml | 125 ml | 250 ml | 500 ml | 625 ml |
| 50:1 | 20.0 ml | 100 ml | 200 ml | 400 ml | 500 ml |
| 100:1 | 10.0 ml | 50 ml | 100 ml | 200 ml | 250 ml |
| Engine Type | Era / Age | Typical Ratio | Break-In Ratio | Recommended Oil Grade |
|---|---|---|---|---|
| Modern Outboard | Post-1990 | 50:1 | 25:1 – 50:1 | TC-W3 or Full Synthetic |
| Mid-Era Outboard | 1980–1990 | 40:1 | 25:1 | TC-W3 |
| Older Outboard | 1970–1980 | 32:1 | 20:1 | TC-W3 / TC-WII |
| Vintage Outboard | Pre-1970 | 24:1 – 16:1 | 16:1 | TC-WII or Mineral |
| Portable / Small HP | Any | 50:1 | 25:1 | TC-W3 |
| PWC (Jet Ski) | Post-1990 | 50:1 | 25:1 | TC-W3 Synthetic |
| High-Performance | Any | 50:1 – 100:1 | Per manual | Full Synthetic Racing |
| Oil Type | Standard | Best For | Notes |
|---|---|---|---|
| TC-W3 | NMMA TC-W3 | All modern 2-stroke outboards | Current industry standard |
| Full Synthetic | TC-W3 or higher | High-performance, all modern | Better protection, may allow 100:1 |
| Semi-Synthetic | TC-W3 | General use modern engines | Good balance of cost and protection |
| Bio-Degradable | TC-W3 compliant | Eco-sensitive waterways | Safer for environment |
| TC-WII | NMMA TC-WII | Older pre-1990 engines | Less cleaning additives than TC-W3 |
| Mineral Base | SAE 30 / 40 | Vintage pre-1970 engines | Original specification for vintage |
| Racing Synthetic | API TC / JASO FD | High-performance racing | Allows leaner 100:1 mixes |
Two-stroke outboard engines require oil mixed with the gasoline. The mix of oil and gas lubricates the internal parts. Without it the engine quickly seizes up Some outboard motors have oil injection that mixes automatically, but many older models you must mix oil and gasoline in the main tank each time it is empty.
You call that premix system.
How to Mix Oil and Gas for Two-Stroke Outboards
The usual ratio for two-stroke outboards is 50:1, so around one pint oil for six gallons regular gasoline or 100 ml for 5 liters. Almost all current models require that 50:1 mix. Mercury, Mariner, Tohatsu, Johnson and Evinrude all advise that.
The engine lubricates with oil mixed with gasoline according to that ratio. Four-stroke engines have a sump, two-stroke do not.
Some Yamaha outboards have a label with 100:1. If your engine has such mark, you can use that mix, but buy oil that meets the 100:1 lubrication standards, not simply TCW-3. Synthetic two-stroke oil with low-temperature dispersants reduce varnish and carbon deposits, so this reduces plug problems and improves the reaction of the throttle.
It smokes and smells less, so emisions are lower in 100:1 than other oils in 50:1. Even so 100:1 does not work for everything (it has only 1% oil), while 50:1 has double, so 2%.
New two-stroke boat motors have a break-in period with a richer mix. Usually you use 25:1, so double oil. Unleaded gasoline with at least 87 octane is needed, but 89 is better for the performance.
If you add too much oil in the fuel mix, the engine will smoke a lot and probably foul the plug. Too much oil causes smoky exhaust, weak spark, fast fouling of the spark plug and maybe of the carburetor jet.
Gear made before 2003 widely wants 32:1, after 2002 use 40:1 or 50:1. For models from the 1960s new 50:1 oils in 25:1 mix are safe. If the oil meets the motor minimums, you mix it.
Quicksilver works for almost each outboard engine. FC-W is the title that most makers require for four-stroke. Two-stroke oil has additives that react with the air and break down over time, because it burns with the gasoline.
