Briggs & Stratton 290000 Operating & Maintenance Instructions page 15

CARBURETOR ADJUSTMENT
WARNING
The manufacturer of the equipment on which this
engine is installed specifies top speed at which the
engine will be operated. DO NOT EXCEED this speed.
Differences in fuel, temperature, altitude or load may require
minor carburetor adjustment. Air cleaner and its cover must
be assembled to carburetor before starting engine.
The carburetor on this engine is low emission. It is
equipped with an idle mixture valve with a limiter (see
inset), which allows some adjustment, and an idle speed
adjustment screw. DO NOT remove limiter caps. DO NOT
force beyond limits.
TO ADJUST CARBURETOR
Single barrel carburetor
CARBURETOR
THROTTLE
LEVER
IDLE MIXTURE
VALVE
Two barrel carburetor
IDLE SPEED
SCREW
IDLE
CYL
MIXTURE
# 1
VALVES
CYL
# 2
[1] Start engine and warm up approximately 5 minutes
before adjusting.
[2] With engine running, place throttle control in SLOW.
[3] Rotate carburetor throttle lever against the idle
speed screw and hold it.
[4] Turn idle speed screw to obtain 1400 rpm (1200 rpm
on two barrel carburetor).
[5] While still holding carburetor throttle lever against
idle speed screw, turn idle mixture valve with limiter
cap. DO NOT remove limiter cap. DO NOT force
beyond limits.
[6] On two barrel carburetor: set cylinder #1 idle mixture
valve midway between limits. Then set cylinder #2
idle mixture valve midway between limits, while
holding carburetor throttle lever against idle speed
screw.
GOVERNED IDLE SPRING
[1] Readjust the idle speed to 1200 rpm, if governed idle
[2] Release carburetor throttle lever. Move throttle
Note: Engines operated at about 3000 to 5000 feet (900 to
1500 meters) above sea level may require a high altitude
carburetor main jet. If erratic performance is observed,
IDLE SPEED
contact a Briggs & Stratton Authorized Service Dealer for
SCREW
cost to install/purchase a high altitude carburetor main jet.
LIMITER
CAP
CARBURETOR
THROTTLE
LEVER
15
ADJUSTMENTS
GOVERNED IDLE SPRING
(RED OR WHITE)
spring is red, or 900 rpm, if governed idle spring is white.
control to FAST position. Engine should accelerate
smoothly. If it does not, readjust idle mixture valves
slightly counterclockwise.
EXHAUST
MANIFOLD