Saito FG-14C Owner's Operating Instruction Manual - Mechanical Faults
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The low-speed needle valve is set at the factory so that
idle rpm may be between 1,800 and 2,100 rpm.
In principle, a carburetor is adjusted by first achieving
highest rpm with the high-speed needle valve and then
performing idling (low-speed rpm) with the throttle valve
and the low-speed needle valve. Unless peak rpm is
achieved, idling adjustment will be difficult to adjust and
will not be stable.
• After filling the tank, start the engine and move the
throttle to the fully open position.
• Turn the main needle valve screw clockwise (refer
to Figure 5, page 7) with the carburetor adjustment
bar (provided in the accessories package) or a small
screw driver and adjust to achieve peak rpm. Use a
tachometer to verify rpm.
CAUTION:
Never over-close the main needle
valve. Doing so could cause knocking,
preignitions and/or loosening of the propeller nut.
If you see that you have over-closed the main needle
valve, immediately turn the main needle counterclockwise
to richen the setting.
• Next, close the throttle valve until the engine
operates stably and with an idle rpm of around 1,700
rpm. Do this by adjusting the low-speed needle
valve with the carburetor adjustment bar (or small
screwdriver) and manipulating the throttle valve via
the throttle stick on the transmitter.
• After reaching the stable 1,700 rpm, slowly open
the throttle fully. If the rpm starts to decrease, or
rapidly increases, adjust the low-speed needle valve
carefully until the changes are smooth from idle to
peak rpm.
• After the previous steps have been accomplished,
repeat the process from idle to high rpm quickly.
If the rpm does not reach peak, but stutters as the
throttle moves from low to high, re-tune the main
needle valve and perform the process from idling to
peak quickly.
• Repeat the process until the response is a smooth
transition from idle to peak rpm.
Final Adjustment of the Carburetor
Step III.
If the engine accelerates correctly, set it at
idle speed and accelerate to full speed. Repeat twice
more. If the engine functions correctly, go to Step IV.
If it cuts out, open the low-speed needle valve by 5 to
10 minutes more. If the engine does not respond to
acceleration fast enough, keep closing the low-speed
needle until the engine starts to cut out in response to
throttle opening. At that point, re-open the low-speed
needle by 5 to 10 minutes.
Step IV.
If the engine reacts correctly, set it at full
speed. If the revolutions do not drop, the engine has
been adjusted successfully. If the revolutions seem to
drop, open the high-speed needle by about 5 to 10
minutes.
Subsequent runs may be made while slightly leaning out
the mixture with each tank full of fuel. Forty minutes is
considered sufficient time for normal break-in prior to
the first flight.
If the engine does not start:
• Check the spark plug. Replace if needed.
• Check the fuel lines.
• Check for proper mechanical function by turning the
engine over.
• Check that the carburetor is correctly installed.
Mechanical Faults
If the engine cannot be turned over easily:
• If your engine is mounted inverted it is possible
the cylinder is flooded. Remove the spark plug and
rotate the propeller to clear the excess fuel before
moving on.
• It is possible the conrod or the piston has seized. Do
not force the engine to turn over. Return the engine
for service.
Engine Maintenance
Do not needlessly disassemble your Saito single-
cylinder engine. If you must disassemble your engine,
please refer to the following steps.
• Cylinder screws should be loosened in a crisscross
pattern.
• Assemble the cam gear lining up the timing mark
at the “6 o’clock” position. The crankshaft must be
positioned at the “12 o’clock” or “top dead center”