“ KOMPRESS ” OWNER’S MANUAL REL . 2.2
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Copyright by
FLY
Products
s.r.l.
Page
17
Carburetor Adjusting
Standard carburetor setting
The carburator has two screws for adjustment, one screw marked
L
adjusting idle speed and low rpm and one screw marked
H
for high rpm.
In order to make the adjustment, tighten clockwise then unscrew: screw
L
from 3/4 (three quarter) turn to one full turn, screw
H
from 1 1/4 (one and
a quarter) to 1 1/2 (one and a half) turn This adjustment is done for the air
filter Air Box (Kart model), we advise this kind of air filter.
Furthermore, we recommend attaching a small security-cable to the air
filter, to avoid it slipping off and hitting against the propeller.
These adjustments can change based on weather conditions and flight
altitudes.
The ideal mixture is reached when the insulator of the spark plug is
light brown (the color of coffee with milk); if the colour is black, the
mixture is too rich, therefore turn screw
H
clockwise 1/8 round per time.
If the spark plug is grey/white, the mixture is lean, therefore turn screw
H
and
L
counterclockwise always 1/8 round per time. Remember that if the
mixture is too lean, THE PISTON CAN SEIZE.
You can see better the color of the spark plug by running the engine for 20 seconds at full throttle
and switching it off suddenly without letting it slow down.
Once you have found the perfect mixture do not change it unless you change where you fly or the
conditions you fly in, since the register screws can be damaged by continuous adjustments.
Keep in mind that these setting are extremely sensitive and the total sum of all adjustment you
make to the screw should not exceed ¼ of a turn. Increments of 1/10
th
of a turn are already
sufficient to change engine performance.
In particular be careful not to run your machine at the “too poor” of a fuel to air-mixture, as this
can result in possible overheating and engine damage due to lack of cylinder lubrification.
Pay much attention to the carburator setting at the maximum since if this mixture is too poor, it can
result in engine damage. No damage is done if the setting is too rich. Therefore, when in doubt, it
is better to have carburation, at the maximum rpm, somewhat more on the rich side.
A verification of carburation can be done after the engine has run 20-30 minutes checking of the
colour of the spark plug electrode. If the electrode is brown the carburation is correct. If is grey, its
poor and if its is black its rich.
Attention: If the carburation should happen to be difficult to adjust by listening to engine runs, this
means that the fuel tube is absorbing air from the pump (in this case is better to change it) or else
from the connections between the tank and the carburator. The air bubbles are easily seen, while
the engine is running they are seen passing through the tube.
