O.S. Engines 12TG-PX - Manual (Page 16)

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In case of the 12D carburetor
In case of the 12E carburetor
Carburetor Body
Mixture Control Screw
Throttle
Lever
REALIGNMENT OF METERING NEEDLE AND
MIXTURE CONTROL SCREW
In the course of making carburetor adjustments, it
is just possible that the Metering Needle and the
Mixture Control Screw may be inadvertently
screwed in or out too far and thereby moved
beyond its effective adjustment range.
The basic positions can be found by rotating the
Metering Needle until its slotted head is flush with
the ball link body.
Slide Valve
Carburetor Body
Metering Needle
Rotate the Metering
Needle until its slotted
head is flush with the
ball link body. This is the
basic position.
Ball Link
Rotate the Mixture Control
Screw until its slotted
head is flush with the ball
link body.
This is the basic position.
Note:
Readjustment of the needle-valve may be
necessary to allow for changes in fuel formula,
gear ratio, clutch engagement point and muffler.
Also, needle setting may vary to atmospheric
conditions within the day. Readjust it according to
actual engine running.
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TROUBLE SHOOTING Symptom
Cause Corrective action
Engine fails to fire.
Fuel tank is empty.
Fuel not reaching the engine. Fill the tank with fuel and repeat
Priming procedure.
Glowplug element is burnt out.
Glowplug battery discharged Replace glowplug.
Recharge or replace the battery.
Clogged fuel filter
Air cleaner and silencer inside is dirty.
Clean or replace fuel filter.
Replace cleaner element and clean inside silencer.
Over priming Remove glowplug and pump out excess fuel.
Fuel tubing is disconnected. Connect fuel tubing securely.
Fuel tubing is kinked, split or has a hole. Check the tubing carefully and replace if necessary.
Incorrect servo linkage Connect correctly after setting servo at neutral.
Reverse rotating direction of starter box.
Mare sure it rotates counter clockwise seen
from crankshaft side.
Recoil starter slips.
Inject cleaner spray into starter cord crevis
on the body.