Castrol A747 is a CASTOR/SYNTHETIC racing engine oil specifically designed for use in highly stressed, high performance, 2-stroke engines using premixed fuels, including water-cooled, road racing go-kart engines. A747 has been developed for race conditions where combustion chamber deposit control is essential.

It is only recommended for premix systems. Its viscosity is too high for use in oil injection systems. Castrol A747 is recommended only for very high performance two-stroke engines. If used in lower performance, lower revving engines, excessive deposit formation may result.

Castrol A747 also contains special additives to prevent throttle slide sticking in the wet weather conditions and may be used mixed at fuel/oil ratios of up to 40:1.