Home > Fuel Mixture Ratios
|Year Manufactured/ Notes*||Ratio||1 gal. gas||2 gal. gas||5 gal. gas|
|1931 to 1978||10:1||12.8 oz. oil||25.6 oz. oil||64 oz. oil|
|1978 on (older converted models*)||25:1||5.12 oz. oil||10.24 oz. oil||25.6 oz. oil|
|Roller bearing models ONLY** (25:1 recommended)||50:1||2.56 oz. oil||5.12 oz. oil||12.8 oz. oil|
To calculate other fuel mix ratios, use CSGNetwork's online Marine Gas Oil Mixture Ratio Calculator.
Note: Outboards equipped with a Bing carburettor can use the 25:1 ratio.
All motors manufactured from January 1978 are designed to operate on a 25:1 petrol (gas)/oil ratio.
Motors manufactured since 1967*** can satisfactorily use this ratio, providing the following modifications are made:
We recommend Seagull Two-Stroke oil, however, if this is unobtainable, use a good quality two-stroke oil.
**The 50:1 ratio is NOT RECOMMENDED for any British Seagull Outboard. If you know or don't know the model of your outboard, use 25:1 or better.
***Motors built prior to 1967 should retain the 10:1 petrol oil ratio.