Solvent-Washed Gum

The solvent-washed gum content test gravimetrically measures the amount of residue after evaporation of the fuel and subsequent heptane wash. Solvent-washed gum measures gums that are both fuel-soluble and fuel-insoluble. The fuel-insoluble gums can clog fuel filters. Both types of gum can be deposited on surfaces upon evaporation of the fuel. ASTM D4806 Requirement: a maximum solvent-washed gum content of 5.0mg/100mL.