2001 Mercury Mariner 50-60HP Factory Service Manual, Page 182Get this manual
CARBURETOR
Inspection
1Inspect needle and piston valveReplace if worn or damaged2Measure auto enrichener resistanceReplace if out of specification
Auto Enrichener Resistance 15-25 68F (20C) 3Perform piston valve height test belowPiston Valve Height Test: aMeasure piston valve height bConnect to 12 battery cWait several minutes dMeasure piston valve height 4Replace auto enrichener if no change was observed