ship operators need to remain vigilant when dealing with high sulphur fuels. sulphur fuels will have on engine lubrication. climbing. says Ouvrier-Buffet. the right alkalinity to match the fuel sulphur level. sulphur levels. burning very high sulphur fuels in other areas. per cent will be permitted by IMO Annex VI. piston crown and the ring pack through the scavenge ports. deposits on the top land and also in the grooves. lub oil stagnation and deposits," explains Ouvrier-Buffet. normally true. to switch to a lub oil with a BN higher than 70.