A marine outboard motor having an internal combustion engine comprising: an engine block having at least one cylinder; and a valve train comprising: a cam; a valve assembly including a valve and a valve spring configured to bias the valve towards a closed position; a roller finger follower having a valve end and a pivot end; and a pivot post extending from a fixed body of the engine block at the pivot end of the roller finger follower, the pivot post defining a contact surface about which the roller finger follower pivots when deflected by the cam during use; wherein the pivot post is moveable relative to the fixed body in a first longitudinal direction against the action of the valve spring, characterized in that a removable shim is disposed between a bearing surface of the fixed body and a portion of the pivot post to space the pivot post from the fixed body in the first longitudinal direction and thereby reduce an amount of lash between the cam and the roller finger follower, wherein the removable shim is dimensioned to fit at least partly around a shaft portion of the pivot post and has an open shape configured to allow the removable shim to be positioned around the shaft portion from a transverse direction to adjust the amount of lash between the cam and the roller finger follower. an engine block having at least one cylinder; and a valve train comprising: a cam; a valve assembly including a valve and a valve spring configured to bias the valve towards a closed position; a roller finger follower having a valve end and a pivot end; and a pivot post extending from a fixed body of the engine block at the pivot end of the roller finger follower, the pivot post defining a contact surface about which the roller finger follower pivots when deflected by the cam during use; wherein the pivot post is moveable relative to the fixed body in a first longitudinal direction against the action of the valve spring, characterized in that a removable shim is disposed between a bearing surface of the fixed body and a portion of the pivot post to space the pivot post from the fixed body in the first longitudinal direction and thereby reduce an amount of lash between the cam and the roller finger follower, wherein the removable shim is dimensioned to fit at least partly around a shaft portion of the pivot post and has an open shape configured to allow the removable shim to be positioned around the shaft portion from a transverse direction to adjust the amount of lash between the cam and the roller finger follower. a cam; a valve assembly including a valve and a valve spring configured to bias the valve towards a closed position; a roller finger follower having a valve end and a pivot end; and a pivot post extending from a fixed body of the engine block at the pivot end of the roller finger follower, the pivot post defining a contact surface about which the roller finger follower pivots when deflected by the cam during use; wherein the pivot post is moveable relative to the fixed body in a first longitudinal direction against the action of the valve spring, characterized in that a removable shim is disposed between a bearing surface of the fixed body and a portion of the pivot post to space the pivot post from the fixed body in the first longitudinal direction and thereby reduce an amount of lash between the cam and the roller finger follower, wherein the removable shim is dimensioned to fit at least partly around a shaft portion of the pivot post and has an open shape configured to allow the removable shim to be positioned around the shaft portion from a transverse direction to adjust the amount of lash between the cam and the roller finger follower.