Check the condition of the spark plug, make sure the ingnition timing
is correct, service the air cleaner element, decarbonize the exhaust
tube
If you machine has run properly up to this point, it is possible that
the problem is elsewhere; changing the carburetor settings in such
a case would probably be a waste of time.
- Set the carburetor so that the engine delivers satisfactory power
with the throttle valve opened.
- If the air-fuel mixture is too lean, the engine tends to overheat and
may be seized. On the other hand, if it is too rich, the spark plug
easily gets wet and causes misfires. The proper mixture varies
depending on atmospheric conditions. Taking these conditions into
consideration, adjust the carburetor settings properly.
NOTE
Keep in mind that the carburetor components that regulate fuel
flow and the screw that control the flow of air must be tight.
Standard Settings
EC / MC / SM 2005 -
108
-
Correction factors:
(For altitude or temperature changes).
1.
Find the correction factor to adjust the carburetor.
Example: 1000 meters altitude with an air temperature of 35 °C. The
correction factor is 0,94.
2.
Using the correction factor, select the correct slow jet and main
jet.
Example: For a correction factor of 0,94 multiply the jet size by that
number.
Idle jet: # 50 x 0,94 = #47.
Main jet: # 162 x 0,94 = # 158.
3.
Find the correction factor on the Jet Needle / Air Screw chart and
change the jet needle clip position and air screw opening as indicated.
- Jet needle clip setting: from the 3rd groove to the 2nd groove.
- Air screw opening: 1 1/2 + 1 turn = 2 1/2 turns out.
NOTE
For the following recommendations to be accurate, you must
use the standard settings as a base-line. Also do not change
any of the settings until you have determined what changes
are necessary. All specifications are based on the use of the
fuel and oil specified.
FUEL
Throttle valve
Idle jet
Needle
Main Jet
UNLEADED
7
38
N1EC
185
LEADED
7
35
N1ED
160
Correct
Too lean
Too rich
Insulator is dry & light tan color
White color insulator
Insulator is wet & black color
Replace the main jet to one
step larger
Replace the main jet to one
step smaller
Spark plug condition
