A two-stroke outboard carburetor may need to be cleaned or rebuilt if it's not idling properly, or if the motor hasn't been started in several months. A dirty carburetor can't regulate the air and fuel mixture properly, which can cause stalling. A two-stroke engine needs a clean carburetor to avoid running lean, which can damage the motor.
 
This service and tuning guide provides the recommended factory stock jetting for every WH series carb model. It also includes troubleshooting and instructions on how to set float heights as well as rebuilding the fuel pump. You might also need to re-jet a two-stroke outboard carburetor as you tune, modify, or run your motor in different atmospheric conditions.
 
Our Mercury WH Series Dual Float Carburetor Service Manual in PDF for the Mercury 2.0 and 2.4 Liters (Black Max, XR2, XR4, 135 HP, 150, 175 HP, 200 HP, and 225 HP) is available here for immediate download.
 
This 17-page Service Manual covers WH carb models found in 1977, 1978, 1979, 1980, 1981, 1982, 1983, 1984, 1985, 1986, 1987, 1988, and 1989 model year Mercury Marine / Mariner V6 2-Stroke outboards.
 
This is for immediate download in PDF format.