Rotek EG4-0210-5 User And Maintenance Manual Download

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6.5.6. Speed setting

The actual speed of the motor is set up over a mechanically adjus-
table speed governor. If there are just small deviations the rotational
speed can be set via the adjusting screw. Because the mechani-
cal regulator always has a negative deviation, adjust the rotational
speed without load to about 2-4% above the target speed. At full
load the rotational speed can be 2-4% below the set.
If the deviation is too big, try if the engine reacts on speed changes
by changing the throttle setting.
The change of the throttle mechanism has to be effortless and
should not be in idle or full-gas position. If the engine don't
react on throttle changes - stop trying to change the
speed setting. Proceed with below described proce-
dure.

Is the deviation too big, the link can be readjusted. At still standing
engine the regulation arm will be pulled to full-gas position by the
main spring.
Unhook the throttle link at the carburator (unhook bounce spring -
pull carburator throttle valve to idle position and remove the throttle
link to the top).
If you turn the carburator throttle valve to full-speed position, the
end of the throttle link should withstand 5-7mm to full-speed positi-
on (needed spare for regulation). If not you have to open the tommy
screw on the regulation arm.

Adjust the regulation arm to reach the needed spare for regulati-
on - end of throttle link must withstand 5-7mm over the full-speed
position of throttle valve. The axle of the regulation arm have to be
in position full-speed (standard arm position at still standing engine).
Fasten the tommy screw and replace throttle link and bounce spring
to the carburator. Restart the engine and adjust the speed like de-
scribed above.

If the tommy screw is too short you van also longer the main spring
by bending the ends of the spring.

The main spring has no influance to the engine speed. It prevents only

fluttering of the throttle link (the throttle link is allways under tension)

6.5.7. Governing behaviour

The mechanical governer can be influenced in its regulation in diffe-
rent ways. The governing (how much the actual speed deviates from
the ideal speed) and the oscillating (engine speed oscillates arround
ideal speed) are important. These two characteristics disagree with
each other. Optimal balance is reached when the speed changing
causes a 1-time low oscillation.
This means: set up the speed without load. Then burden the motor
up with maximum load. Now the speed must first sink, then become
higher than the rated speed and then final go back to rated speed.
Engine speed should not oscillate around the rated speed.

To improve the governing, the regulating spring as well as the bounce

spring can be hung on different positions - see schamtics under 6.5.6.

Normally a allready marked rated speed has to be reset after changing

the spring position.
Normally it is not necessary to change the speed or the behaviour. At

too low engine speed first check for any other causes of error (air filter,

fuel, valves, etc.)!

6.5.8. Muffler and colours of exhaust fumes

Backfire can be a result of loose screws on the outtake-manifold or
the muffler. In that case the fit of the screws as well as the state of
the gaskets should be checked. The exhaust pipe should be leak
and damage free

Residue must be removed from the exhaust pipe and the muffler. How-

ever, such residue indicates that either the wrong fuel is being used or

that oil is being burnt.

Too much exhaust back pressure can overheat the engine.

The colour of the exhaust gas can be an indication of the current
operation state of the motor:

motor is smoking
white or grey

water in the
fuel

drain the fuel tank

motor is smoking blue

motor oil is
being burned

check the oil level, valve guides,
compression and the fuel
(no 2-stroke fuel!)

motor is smoking
black