Specifications

21
MAIN MIXTURE
SCREW
MAIN MIXTURE
SCREW
32
33
34
SMALL PIECE OF WIRE
HOLE IN CONTROL BRACKET
MOUNTING
BOLTS
HOLE IN
CHOKE
ACTUATING
LEVER
HOLE IN CHOKE LEVER
HIGH SPEED
ADJUSTMENT SCREW
THROTTLE
CRACK
SCREW
IDLE MIXTURE
SCREW
GOVERNOR
ADJUSTING
LEVER
HIGH SPEED
ADJUSTMENT
SCREW
LOW SPEED
ADJUSTMENT SCREW
MOVE THE CONTROL
LEVER IN THE HIGH
SPEED POSITION
THROTTLE CRACK SCREW
IDLE
MIXTURE
SCREW
Engine Speed and Mixture
Adjustments
5-15 HP Vertical Shaft Engines
The first step is adjusting the speed control bracket
for full choke operation. Loosen the two speed
control bracket mounting bolts and move the control
lever to the full high speed/full choke position. Insert
a piece of wire through the hole in the speed control
bracket, the choke actuating lever, and the choke
lever (diag. 32). When all three holes are in alignment
retighten the speed control bracket mounting bolts.
The second step is adjusting the main and idle
fuel mixtures. Start the engine and allow it to warm
up to normal operating temperature (3 - 5 minutes).
Set the speed controls to the HIGH or FAST position,
then turn the main mixture adjustment screw in
(clockwise) slowly until the engine begins to run
erratic (lean). Note the position of the screw. Now,
turn the screw out (counterclockwise) until the
engine begins to run erratic (rich). Turn the screw
in (clockwise) midway between these two positions.
This will be the best setting.
Set the speed control to the IDLE or SLOW position.
Adjust the idle mixture screw following the same
procedure used to adjust the main mixture adjustment
screw.
NOTE: SOME CARBURETORS HAVE FIXED
MAIN JETS. THE ABSENCE OF THE ADJUSTING
SCREW INDICATES A FIXED JET AND NO
ADJUSTMENT IS NECESSARY.
The third step is setting engine speeds. The
correct engine operating speeds are listed on card
30 of the Tecumseh Master parts manual microfiche,
or the computer parts look-up program (Part Smart
or Plus One). The most common speed control
bracket (diag. 33) has the high speed adjustment
screw located on the speed control lever. The low
speed adjustment screw is the throttle crack screw
on the carburetor body. Another common speed
control is the governor override system (diag. 34).
This system has a similar speed control bracket
along with a governor adjustment lever which is
attached to the engine block. Both the high speed
and low speed adjustment screws are located on
the governor adjusting lever.