Try to adjust the gas your self by following the given procedure,
1) Open the bonnet
2) Loosen the lock nut of adjustment screw at power T.( Installed on gas pipe in-between carburetor and cng regulator or cng kit )
3) Now start and accelerate the engine to 3000 / 3500 RPM and hold steady. (Large engines use 2000 2500 RPM).
4) Turn the adjustment screw clockwise slowly until the engine speed gets dropping, Stop here, and now turn the screw anti clockwise till the speed again start dropping and at this point revert back turning the screw clockwise very slowly until the engine speed becomes on its peak.
5) Lock the adjustment screw at this position.
4) Let engine idle and adjust the idle screw(Brass or plastic screw installed on regulator ) until the engine runs best (not too rich and not too lean).
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