We assess the ¹⁴C plateau tuning technique used to date marine sediments and determine ¹⁴C marine reservoir ages. We identify problems linked to assumptions of the technique, the assumed shapes of the ¹⁴C / ¹²C records, and the sparsity and uncertainties in both atmospheric and marine data. Our concerns are supported with carbon cycle box model experiments and statistical simulations, allowing us to question the ability to tune ¹⁴C age plateaus in the context of noisy and sparse data.