| abstract |
Trunk piston marine engine lubrication, when the engine is fueled by heavy fuel oil, is effected by a composition comprising a major amount of an oil of lubricating viscosity containing at least 50 mass % of a Group II basestock, and respective minor amounts of an overbased metal hydrocarbyl-substituted hydroxybenzoate detergent other than such a detergent having a ba-sicity index of less than two and a degree of carbonation of 80% or greater and at least 1 mass % of a hydrocarbyl-substituted car-boxylic acid, anhydride, ester or amide thereof. Asphaltene precipitation in the lubricant, caused by the presence of contaminant heavy fuel oil, is prevented or inhibited. |