1996-2005 Suzuki DF40, DF50 Four Stroke Outboard Service Manual, Page 413Get this manual
DF40DF50 "K3" (03) model 14-2 Item Unit Data DF40T DF40QH DF50T50WT DF50WQH
FUELOIL
Suzuki highly recommends that you use alcohol-free unleaded gasolinewith minimum pump octane rating of 87method) or 91 (Research method)However, blends of unleaded gasoline and alcohol with equivalent octane content may be used
Engine oil
API classification Viscosity rating
SE, SF, SG, SH, SJ SAE 10W-40
Engine oil amounts
L (USImpqt)
2.2 (2.31.9)Oil change only 2.4 (2.52.1)Oil filter change SUZUKI Outboard Motor Gear Oil (SAE #90 hypoid gear oil)