Service manual

MERCARB 2 BARREL CARBURETOR
SERVICE MANUAL NUMBER 26
90-861329--1 MARCH 1999 Page 5B-13
2. Turn idle mixture needle in until lightly seated, then back needle out 1-1/4 turns.
72281
a
a-Idle Mixture Needle
Final Idle Speed and Mixture
EMISSIONS CARBURETOR
Sealed Carburetor Mixture Screw
The carburetor on this engine has a seal on the carburetor mixture screw. This seal prevents
adjustment of the fuel mixture setting.
CAUTION
Do not remove mixture screw seal and/or attempt to adjust fuel mixture setting.
Tampering with the mixture setting on this engine could affect the exhaust
emissions level, thus voiding the emissions certification. This seal should only be
removed by an authorized dealer or emissions testing agency.
NON-EMISSIONS CARBURETOR
IMPORTANT: Boat must be in the water and engine at normal operating temperature
to accurately check and adjust idle speed and mixture.
Carburetor should be set so that engine idles smoothly within range given under “Specifica-
tions,” with boat in the water, engine at normal operating temperature and drive unit in for-
ward gear. To adjust idle speed and mixture, proceed as follows:
IMPORTANT: DO NOT attempt to compensate for other engine problems (incorrect
ignition timing, faulty ignition components, low compression, vacuum leaks, etc.)
with carburetor adjustments. This will only cover the problem, which must be cor-
rected if engine is to achieve maximum fuel economy and performance.
1. Connect an accurate shop tachometer to engine.
IMPORTANT: DO NOT turn idle mixture needle tightly into seat, as damage to needle
and/or seat may result.
72281
a
a-Idle Mixture Needle
INDEX