Mercury Mariner Outboards 2.2 / 2.5 / 3.0 Service Shop Manual, Page 28Get this manual
Troubleshooting Problems, which sometimes are thought to be caused by the fuel system, may be something completely different Trouble with items 1-2-3-4, listed on the right, also may give the impression that problem exists in the fuel system1234Spark plug Ignition spark voltage Cylinder compression Reed valves
PROBLEM:
Engine Will Not Start or Starts Hard When Cold Engine Idles Rough and Stalls
Possible Cause
Engine Hesitates upon Acceleration Engine Runs Uneven or Surges
Corrective Action
Improperly mixed fuelcontaminants (water, dirt, etc in fuel Fuel tank air vent closed or restricted Restricted fuel line or fuel shutoff valve Carburetor flooding Restricted fuel strainer Idle speed screw out-of-adjustment Improper carburetor float setting Engine runs lean Engine runs rich
Check fuel in fuel tank and replace if necessaryCheck air vent in filler capAir vent must be fully open and free from restrictionsCheck and replace or lean fuel line or fu el shutoff valveSee following Check and clean fuel strainerRefer toCarburetor Adjustment" in this section Reset float to correct levelSee following See following