Motortech VARIFUEL2, Assembly Instructions Manual

Page: 37 / 50

6 Operation
Rev. 09/2020 37
– For gases with low fuel value, it may be necessary to set the balance/zero pressure regulator
to a slight overpressure (max. 5 mbar for starter speed) for the engine start phase. Do not
set the overpressure too high, because too much gas content in the engine can lead to start
problems. As soon as the engine is running, set the balance/zero pressure regulator back to
pressure balance in idle at nominal speed. This setting guarantees that adequate suction
pressure exists at the gas inlet at engine start.
– Other reasons may be that, for example, the nominal diameter of the flexible gas line is
smaller than that of the gas mounting flange or the diameter of the gas mounting flange is
too small to discharge sufficient gas into the engine at low suction pressure. Check in any
case whether the gas supply of your VariFuel2/2+ gas mixer is sufficiently dimensioned. If
you have any questions, contact MOTORTECH (see
Customer Service Information on
page 46).
Engine Does Not Reach Nominal Power
With the prescribed emissions, the engine does not reach its nominal output. The following
scenarios might be possible:
Scenario 1:
– The opening of the fuel ring is in the range between 15 % and 80 %.
– The nominal output is reached by enriching the mixture.
– At the gauge port of the VariFuel2/2+, an underpressure greater than 30 mbar is measured.
In this case, it is necessary to increase the air supply. This can be achieved based on the fol-
lowing measures:
– Check air filter for dirt or excessive back pressure. Clean or replace air filter if necessary.
– Check underpressure in the air intake line (standard value: –5 mbar to –25 mbar)
– Install a smaller flow body. To do so, please contact MOTORTECH (see Customer Service
Information on page 46).
Scenario 2:
– The opening of the fuel ring is > 95 %
– The nominal output is not reached by enriching the mixture.
– An underpressure less than 60 mbar is measured at the gauge port of the VariFuel2/2+.
In this case, it is necessary to increase the gas supply. This can be achieved by carrying out one
of the following measures:
– Install larger flow body
– Use larger gas mounting flange.
To do so, please contact MOTORTECH (see Customer Service Information on page 46).