A process for reducing C2-C9 olefin formation by recycling them to a Fischer-Tropsch hydrocarbon synthesis process and promoting recycled olefins chain growth comprises contacting a gas feed comprising a mixture of H2 and CO with a catalyst in a reactor system at conditions effective to produce a hydrocarbon product stream including C2-C9 olefins, separating a C2-C9 olefins-rich stream from the hydrocarbon product stream to form a light olefin recycle stream and recycling the light olefin recycle stream to the reactor system at a point in the reactor system where the H2:CO ratio is low relative to the H2:CO ratio in the rest of the reactor system. Depending on whether the initial H2:CO ratio is greater or less than the usage ratio of the selected catalyst, the recycled olefins can be returned to the system up- or downstream of the reactor system.