MERCARB 2 BARREL CARBURETOR - 5B - 9
90-816462 2-695
Preliminary Idle Speed and Mixture
IMPORTANT: The following adjustments will pro-
vide a sufficient idle speed and mixture for start-
ing engine. Final adjustments must be made with
engine running.
1. Back out idle speed screw until it no longer con-
tacts idle cam. Turn idle speed screw in until it just
contacts idle cam, then turn screw in an additional
two turns.
72284
b
a
a - Idle Speed Screw
b - Idle Cam
IMPORTANT: DO NOT turn idle mixture needle
tightly against seat (in the following step), as
damage to seat and/or needle may result.
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
IMPORTANT: Boat must be in the water and en-
gine at normal operating temperature to accu-
rately check and adjust idle speed and mixture.
Carburetor should be set so that engine idles smooth-
ly within range given under “Specifications,” with boat
in the water, engine at normal operating temperature
and drive unit in forward 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
corrected 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
2. If new or rebuilt carburetor has been installed,
turn idle mixture needle in (clockwise) until it light-
ly contacts seat, then back out needle 1-1/4 turns.
This will provide a sufficient setting to allow start-
ing engine.
3. Start engine and run at 1500 RPM until engine
reaches normal operating temperature.
!
WARNING
DO NOT leave the helm unattended while per-
forming idle speed and mixture adjustments, fol-
lowing. BE CAREFUL NOT TO ACCIDENTALLY
ACCELERATE ENGINE WHILE PERFORMING
ADJUSTMENTS.
Summary of Contents for 13
Page 1: ...13 Printed in U S A 90 816462 2 695 1995 Brunswick Corporation GM 4 Cylinder MARINE ENGINES ...
Page 2: ...90 816462 2 695 0 ...
Page 7: ...1 A IMPORTANT INFORMATION GENERAL INFORMATION 72000 ...
Page 15: ...1 B 50617 IMPORTANT INFORMATION MAINTENANCE ...
Page 36: ...1 C IMPORTANT INFORMATION TROUBLESHOOTING ...
Page 74: ...2 A 50633 REMOVAL AND INSTALLATION 4 CYL ALPHA ONE DRIVE ...
Page 88: ...3 A 26790 ENGINE 181 CID 3 0L 4 CYLINDER GM ENGINE ...
Page 137: ...4 A 72079 ELECTRICAL SYSTEMS STARTING SYSTEM ...
Page 170: ...4 B 71855 ELECTRICAL SYSTEMS IGNITION SYSTEM ...
Page 197: ...ELECTRICAL SYSTEMS CHARGING SYSTEM 4 C 72078 ...
Page 237: ...4 D 72747 ELECTRICAL SYSTEMS INSTRUMENTATION ...
Page 250: ...4 E 72938 ELECTRICAL SYSTEMS WIRING DIAGRAMS ...
Page 264: ...5 A FUEL SYSTEM FUEL PUMP ...
Page 271: ...5 B 72681 FUEL SYSTEM MERCARB 2 BARREL CARBURETOR ...
Page 300: ...6 A 50628 COOLING SYSTEM SEAWATER COOLED MODELS ...
Page 309: ...6 B 73665 COOLING SYSTEM CLOSED COOLING MODELS ...
Page 325: ...C 6 EXHAUST SYSTEM MANIFOLD ...
Page 331: ...7 A 71317 POWER STEERING PUMP ...