OILS AIN'T OILS
Do you have enough coffee to stay awake during this tech piece? Or perhaps you suffer from insomnia? If so then read on.
Oils not only lubricate a four-stroke engine but contribute up to 40 per cent of its cooling capacity, so it's essential to use the right oil for your engine.
Until the early fifties most four-stroke oils were mono-grades which required engine owners to use higher viscosity (‘thicker’) oils in summer and lower viscosity (‘thinner’) oils in winter. An example would be using a mono-grade 40-weight oil (which was the basis of early two-stroke outboard oils) in temperatures above 30 degrees and a mono-grade 30-weight oil from 0 to 30 degrees. However, if winter temperatures dropped below freezing, the still relatively viscous oil could create cold starting issues.
This all changed in 1953 when oil specialist Motul introduced multi-grade oils, where oil viscosity increases as the
