23
EMISSIONIZED TC/TILLOTSON
CARBURETOR
The Tillotson carburetor is an emissions grade carb. It has
a married idle and high speed circuitry with limited jet
adjustments on the idle (diag. 3-17).
EMISSIONS CARBURETOR IDLE MIXTURE
ADJUSTMENT PROCEDURES
The carburetor is preset at the factory at a normal setting
required for initial engine operation.
Allow the engine to reach normal operating temperature
(after 3-5 minutes).
Set the engine speed control in the idle position. With the
engine at idle speed (Note: must be less than 2400 R.P.M.
for accurate adjustment). Using a small tip screw driver
that fits through the access hole in the limiter cap, adjust
the mixture screw slowly clockwise until the engine
R.P.M. just starts to decrease. Stop and note this screw
position. Turn the idle mixture screw slowly
counterclockwise. As the engine increases R.P.M.
continue to slowly turn the screw counterclockwise until
the engine R.P.M. starts to decrease. Note this position
and turn the mixture screw back clockwise halfway
between the two engine R.P.M. drop off positions.
Verify the engine will accelerate from low speed to high
speed and that the idle speed remains at the desired
setting.
Once adjustments are complete, center the adjustment
limiter cap between the two stops and press inward to
engage the limiter. The limiter will snap into position and
engage the adjusting screw. All future adjustments should
now be made using the adjusting slot in the limiter cap.
Once the limiter cap is snapped
into place it is not possible to
remove the limiter or to adjust the mixture screw beyond
the limits of the limiter assembly. Make sure that initial
adjustments are made per the above procedure prior to
engaging the limiter cap.
TC/TM, EMISSIONIZED TECUMSEH
CARBURETOR
The Tecumseh emissions diaphragm carburetor has fixed
main and idle jets (diag. 3-18). It uses a married idle and
high speed circuitry. The idle has a metering jet that can
be removed for cleaning. It is covered by a small cap that
must be removed to expose the jet for servicing. No
adjustments or presets are required. The idle jet should
be turned until tight 5-8 inch pounds (0.5 Nm), and the cap
should then be installed to cover the jet.
!
CAUTION
3-17
3-18
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