Specifications

26
Engine Speed and Mixture Adjustments
NOTE
Starting and operating problems may exist when engines
are used at high elevations (over 4,000 feet above sea
level). In cases where a fixed main carburetor is used,
refer to Bulletin 110 for correction.
Engines which are identified as compliant with
CARB (California Air Resources Board) or EPA (US
Environmental Protection Agency) regulations can
NOT be changed from their factory jetting unless
specifically authorized.
Before making any speed or carburetor adjustments be
sure to adjust the governor and control bracket.
To adjust the speed control bracket, determine whether
the carburetor is an adjustable type, then proceed.
Some carburetors may have a choke lever which is
operated by the speed control bracket. To adjust the
speed control bracket for full choke operation, loosen
the speed control bracket mounting bolts and move the
speed control lever to the high speed/full choke position.
Next, insert a small piece of wire through the hole in the
speed control bracket, choke actuating lever, and the
choke lever (diag. 23). When all three holes are aligned
tighten the mounting bolts.
It may be necessary to preset the carburetor mixture
screws.
Tecumseh Carburetors
Engine Model Main Pre-set Idle Pre-set
All models
with float-type
carburetors
1-1/2 turn 1 turn
All models with
diaphragm-type
carburetors
1 turn 1 turn
Some speed control brackets are adjusted by loosening
the speed control bracket mounting bolts and sliding
the bracket all the way to the right and re-tightening the
mounting bolts (diag. 24).
23
SMALL WIRE (DRILL BIT)
HOLE IN BRACKET
HOLE IN SPEED
CONTROL CHOKE
ACTUATING LEVER
HOLE IN CHOKE
LEVER
SPEED CONTROL
MOUNTING BOLTS
22
NON-ADJUSTABLE NO
CHOKE PRIMER
ADJUSTABLE MIXTURES,
CHOKE
IDLE
(Low Speed)
MAIN (High Speed)
SPEED CONTROL MOUNTING BOLTS
24
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