Patent ID: 8703676

Claim:
A trunk piston marine engine lubricating oil composition for improving asphaltene handling in use thereof, in operation of the engine when fuelled by a heavy fuel oil, which composition has a TBN of from 20 to 60 mg KOH/g and comprises or is made by admixing an oil of lubricating viscosity, in a major amount, containing 50 mass % or more of a Group II basestock, and, in respective minor amounts: (A) an overbased metal hydrocarbyl-substituted hydroxybenzoate detergent having a basicity index of two or greater; and (B) 5 to 500 mass % active ingredient, based on the active ingredient mass of (A) of an oil-soluble alkyl-substituted phenol other than a hindered phenol, said oil-soluble alkyl-substituted phenol being selected from the group consisting of alkylbenzenols having a single alkyl group substituent having 9 to 30 atoms in the 2-position or in the 4-position, and alkylnaphthols having a single alkyl group substituent having 9 to 30 atoms in the 1-position or in the 2-position.