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m) Checking the basic carburettor settings
Fine-tuning of idle motion and full throttle can only be carried
out with a well run-in engine.
The carburettor of the built-in FORCE combustion engine stands out for
its material combination of plastic and metal. The low heat absorption of
the plastic, as opposed to a carburettor completely made of metal, reduces
the amount of fuel mixture evaporating prematurely in the carburettor.
Fuel feeding is thus more precise an easier even when the engine is hot.
Carburettor settings remain repeatable and constant during operation.
(1) Main jet needle (idle mix adjustment screw)
The main jet needle is located above the fuel supply to the carburettor. It
is pre-adjusted for the first start of the engine and should not be modified
yet.
The main jet needle regulates the air-fuel mixture at full throttle.
Turn the needle clockwise to lean the mixture (reduce the fuel ratio) or
anti-clockwise to enrich the mixture (increase the fuel ratio).
For the very first start, the main jet needle should be screwed in completely
and then screwed back between two to three revolutions.
(2) Throttle stop screw (idle speed adjustment screw)
The throttle stop screw is the small screw next to the idle speed adjustment screw. It is preset and should not need any re-adjustment. The idle speed adjustment
screw regulates the position of the carburettor slide (the throttle stop) and consequently the carburettor barrel in idle speed.
We recommend a carburettor barrel of approx. 1 - 1.5 mm.
Turning the adjustment screw clockwise widens the barrel, turning it anti-clockwise causes the slide to move further in which narrows the opening.
(3) Air suction hole
The air filter in installed here.
(4) Idle speed mix adjustment screw
The idle speed mix adjustment screw is the little screw on the side of the carburettor linkage. It is pre-adjusted for the first start and should not be modified yet.
The idle speed mix adjustment screw regulates the air fuel mixture in idle speed and during the transition to full throttle.
Turn the screw clockwise to lean the mixture (reduce the fuel ratio) or anti-clockwise to enrich the mixture (increase the fuel ratio).
Depending on the fuel, the glow plug and ambient conditions, some minor adjustments might have to be made later.
In order to restore factory settings, proceed as follows:
• Open the carburettor slide completely.
• Keep the slide open and turn the idle speed mix adjustment screw clockwise as far as it will go.
• Now turn it 7.5 revolutions anti-clockwise.
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