2001 Mercury Mariner 50-60HP Factory Service Manual, Page 131Get this manual
TIMING, SYNCHRONIZING,ADJUSTING
3Connect the Carburetor Tuner to the hose adaptors4Pinch off enrichener lines between carburetors with tubing clamp
CAUTION
When using the old style mercury filled carbtuner (pn 91-809641) install filters (4) (pn 35-18206) in each lineThis will prevent mercury from being drawn into carburetors during an abrupt throttle change