Adjust Throttle Control; Service And Adjustment; How To Adjust The Carburetor - Craftsman 502.270210 Owner's Manual

SERVICE AND ADJUSTMENT
HOW TO ADJUST THE CARBURETOR
The factory settings for the carburetor are for most conditions_ tfthe
engine is operated underthe following conditions, you can adjust
the carburetor mixture+
1. The engine has a loss of power or does not run smooth+
2 A change from summer to winter operation.
3. A 40 degree change in the operation temperature+ The carbure-
tor was adjusted at 80 degree at the factory.
4. The engine is operated above 4,000 feel
If an adjustment is needed, follow the steps below+
1+ With your hand, turn the idle mixture screw in a clockwise di-
rection until you feel some resistance., Turn the main jet screw
in a clockwise direction until you feel some resistance
(Figure 29)
CAUTION: Do not over tighten the idle mixture screw or the
main jet screw. The carburetor" will be damaged.
2+ Turnthe idle mixture screw counterclockwise 1+/4tums_Turn
the main jet screw counterclockwise 15/Bturns+
3+ Start the engine+ Run the engine for several minutes.
4+. Move the throttle control to SLOW position+
5+ Turn the idle mixture screw clockwise untilthe engine begins
to toose speed. Note the position of the slot in the idle mixture
screw.,
6+ Slowly turn the idle mixture screw counterclockwise until the
engine runs rough,+ Note the position of the stot in the idle mix-
ture screw+
7. Set the idle mixture screw between tlle two positionsin steps
5. and 6+
11,,
!2.
8_ Move the throttle control to FAST position+
9,. Turn the main jet screw in a clockwise direction until the en-
gine begins to loose speed (lean mixture)+Note the position of
the slot in the main jet screw+
10+ Slowlyturn the main jet screw in a counterclockwisedirection
until the engine runs rough (rich mixture)+ Note the positionof
the slot in the main jet screw,,
Set the main jet screw between the two positionsin steps 9,,
and 10..
13.
14+
To check the adjustment, operate the engine+ If the engine
stops when the blade(s) are engaged, the carburetor mixture
isset too lean.. Turn the main jet screw counterclockwise 1tl 6
turn.,
if the engine runs rough when the blade(s) are engaged, the
carburetor mixture is set too dch+ Turn the main jet screw
clockwise 1/16 tum+
Again check the engine by engaging and disengaging the
blade(s).. If necessary, repeat steps 12+or 13.
Mixture Screw
Main Jet Screw
Figure 29
HOW TO ADJUST THE THROTTLE CONTROL
For the best engine performance, set the throttle control as follows..
1+ Move the throttle control to the FAST position (Figure 30)+
2+
Loosen the clamp screw so that the throttle control cable
can move in the cable clamp (Figure 31). Do not remove the
cable clamp or disconnectthe throttle control cable from the
engine control lever+
3. Move the engine control lever until the slot in the lever is
aIigned (lines up) with the hole in the control bracket as
shown+
4+ Tighten the clamp screw. Move the throttle control to the
SLOW positionand then back to the FAST position.Check the
alignment of the throttle control lever. See step 3,
5_
The throttle control is now set at the correct speed+ When the
throttle control is at the FAST position, the engine speed is
3400 + or- 100 RPM. When the throttle control is in the
SLOW position,the engine speed is 2150 + or- 100 RPM,,
IMPORTANT: Do not change the engine governor+ if the engine
governor needs an adjustment, go to the nearest Authorized
Service Center: They have the equipment and experience to
make the adjustmenL
F-98668 26
/
ThrottleControl
CHOKE
FAST
SLOW
Figure 30
Engine Control Lever - FAST position
{S10l in leveralignedwith h01e in bracket)
Throttle Control
Cable
Cable Clamp
Clamp Screw
Control Bracket
Figure 31