S&S Cycle MGL Carburetor - Manual (Page 4)

B. Cold Starts:
1. Pull the choke lever up to the fully closed
position. Open the throttle and kick the engine
through two or three times. Then, with the choke
half open, switch on, and the throttle slightly
cracked, kick the engine through. For colder
weather, 50° and below, or for instances where
the engine has not been run recently, it may be
necessary to prime the engine with an additional
kick. After the engine starts, push the choke lever
to the wide open position and jockey the throttle
slightly to keep the engine running.
C. Hot Start:
1. Hot starting does not normally require the use
of the choke. Starting is usually accomplished by
turning on the ignition and kicking with the
throttle closed.
D. Electric Start Models:
1. Close the choke halfway, turn on the ignition,
and with the throttle slightly cracked engage
the starter. After the engine starts, open the
choke and work the throttle slightly until the
engine will idle by itself.
E. Troubleshooting Tip - Engine will not start:
1. Fuel supply empty.
2. Weak or no spark - discharged battery or
faulty magneto.
NOTE: We do not recommend the use of magnetos.
3. Plug gap too wide - we use .020 to .022 plug gap
on our point type ignition engines.
4. Improper ignition timing.
5. Tight tappet adjustment.
6. Improper idle mixture and/or engine RPM
setting.
7. Intermediate air bleed loose.
8. Improper diagnosis of a rich or lean mixture
condition. If the engine fires in the carb, it is too
lean and must be re-primed. Do not continue to
kick the engine over with the switch on until it
is re-primed. If there . is no response after three
kicks or if it pops in the exhaust pipes, it is too
rich. Leave the switch on and open the throttle
a
1 ⁄
4
turn with each successive kick until it fires.
Adjusting the Carburetor
Idle Circuit:
The idle mixture screw, Part No. 54, is initially set during
assembly to 1
1 ⁄
2
turns out from the fully closed position.
Check this and reset the screw to 1 1 ⁄
2
turns before
attempting to start the engine.
Never close the idle mixture screw tightly as damage to
the needle and seating area in the carburetor body may
result.
The throttle stop engine RPM adjustment screw
located on the throttle arm, Part No. 48, is initially set
by holding the throttle closed and turning the screw
until it contacts the throttle arm stop boss. At this
point it is turned an additional
1 ⁄
2
turn clockwise. Start
the engine and warm it up to operating temperature.
Adjust the engine RPM to a slow idle, approximately
600 to 800 RPM. Then turn the idle mixture screw in,
leaning it, until the engine starts to die. Next, turn the
screw back out, richening it, until it starts to die. A
position about halfway between these points, or a
setting of about
1 ⁄
4
to 1 ⁄
2
a turn out from the lean side
of the range is the correct setting. From the fully
closed position this would be approximately 1
1 ⁄
4
to 1 3 ⁄
4
turns. Then set the throttle stop screw to give final
desired RPM idle speed. Idle speeds will vary
according to the individual and the use to which the
machine is put.
NOTE Whenever an intermediate jet change is made,
the idle mixture screw should be readjusted.
Troubleshooting Tip- - Engine will not idle:
1. Improper idle mixture and/or engine RPM setting.
2. Intake manifold air leak.
3. Sticky timing automatic advance mechanism.
4. Foreign material obstructing gas flow to idle circuit.
Intermediate System—
Intermediate jet:
For normal riding conditions, the intermediate range is
used the most. Therefore, close attention must be paid
to jetting the midrange to achieve optimum
performance and gas mileage. Once the engine is
warmed up and the idle mixture and engine RPM screws
set, the bike must be road tested. The intermediate
range is used from right off idle up to approximately
3500 RPM or 50 to 60 MPH depending on gearing. If,
while maintaining a steady speed, popping or spitting
occurs regularly in the air cleaner, the intermediate jet,
Part No. 153, should be changed to the next larger size.
CAUTION
4