2001 Mercury Mariner 50-60HP Factory Service Manual, Page 192Get this manual

EMISSIONS
STRATIFIED VS HOMOGENIZED CHARGE
DFI engines use stratified charge inside the combustion chamber to aid in reducing emissionsAll other models use homogenized chargeThe difference between the two is:

• ATV
• Jet Ski
• Outboard Motors
• Personal Watercraft
• Snowmobiles
• Stern Drives