Aspen 4 is alkylate petrol without oil – suitable for lawnmowers, rotary cultivators, snow blowers, boats and other 4-stroke engines. Ordinary petrol contains ethanol which attracts moisture and can cause engine failures. Aspen Alkylate Petrol contains no ethanol, making it ideal for use in marine environments. To use Aspen Alkylate Petrol in your 2-stroke outboard motor, simply mix Aspen 4 with outboard oil. To minimise the environmental impact, choose a biodegradable oil.