Specifications

15
CARBURETORS AND GOVERNORS
Tecumseh 2-Cycle Diaphragm
Adjustments
NOTE
For meeting emission requirements, some carburetors
have fixed-main or idle jets. The absence of the
adjustment screw indicates fixed jets and no adjustment
is necessary.
Diaphragm-Dual Adjustment
Turn mixture adjusting screws in finger tight to the closed
position, then one (1) turn out from closed position. This
setting is approximate. This will allow the engine to be
started so the carburetor can be fine tuned.
Start the engine and let it warm up for approximately
3-5 minutes. Do not adjust the carburetor when the
engine is cold.
Set the throttle control to idle. If it is a fixed speed
type, manually hold the throttle against the idle speed
adjustment screw.
The throttle lever must be held against the crack
screw for low speed adjustments or all adjustments
will be incorrect and cause poor performance and
unsatisfactory operation.
With the engine idling and throttle lever against the idle
speed regulating screw, turn the low speed adjustment
screw slowly clockwise from the NORMAL setting until
the engine falters. Remember this location. Turn the
screw counterclockwise until engine just starts to sputter
or drops in R.P.M. Remember this location. Turn the
screw clockwise until it is halfway between your first
position where the engine faltered and your last position
where the engine started to sputter. This will be the
optimum low speed setting on your carburetor.
Next run the engine at governed speed. The high speed
adjustments are made basically the same as the low
speed adjustments, with the exception of the settings
being made 1/8 of a turn at a time, from the NORMAL
settings.
NOTE
It may be necessary to re-check the idle mixture
adjustment after performing the high speed
adjustment.
Diaphragm-Single Adjustment
Turn the mixture adjustment screw finger tight to the
closed position, then one (1) turn out from the closed
position. This setting is approximate and will allow
the engine to be started so the carburetor can be fine-
tuned.
Start the engine and let it warm up for approximately
3-5 minutes. Do not adjust the carburetor when the
engine is cold.
Set the throttle control to idle. If it is a fixed speed
type, manually hold the throttle against the idle speed
adjustment screw.
NOTE
If the engine falters or stops after the choke lever is
moved to the "OFF" position, open the mixture adjusting
screw 1/4 turn (counterclockwise) and restart the
engine.
With the engine running, place the speed control in
the "slow" position to make mixture adjustments. Turn
the mixture screw slowly clockwise from the NORMAL
setting until the engine falters. Remember this location.
Turn the screw counterclockwise until the engine just
starts to sputter or drops in R.P.M. Remember this
location. Turn the screw clockwise until it is halfway
between your first position where the engine faltered and
your last position where the engine started to sputter.
This will be the optimum setting on your carburetor.
1
IDLE MIXTURE
SCREW
MAIN MIXTURE
SCREW
NOTE: If no tension
spring is present, it
may be a fixed jet.
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For Discount Tecumseh Engine Parts Call 606-678-9623 or 606-561-4983