Lifan KP4500iE Owner's Manual page 24

Even with a suitable carburettor, the power of the petrol
engine will decrease by about 3.5% for every 300m above
sea level.
If the carburettor is not replaced properly, the decline will be
even greater.
If the generator has been modified with the carburettor for
high-altitudes and then used at normal altitude without
reverting to the normal carburettor, it will produce an
excessive lean mixture causing overheating or serious
damage
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