1986 32' Silverton twin 230hp Crusaders straight inboard.<br />Borg Warner 71c velvet drives. Drive oil clean, engines run<br />smooth. Total time 1200 ?<br /><br />Port engine - at idle no noise - drop in gear - you hear a "clunk" - clunk -clunk as shaft rotates - pick up rpm to 1000rpm noise stops.<br />Foreword or reverse, same noise.<br /><br />On sea trial, everything runs great, no noise, problem has been persistence for 30 hours. Transmission still running normal.<br /><br />I have heard this sound on other velvet drives, and found flexplate ( coupler) would have a broken spring or plate would be<br />cracked. Removed flex plate - appeared normal, except all<br />springs were loose. Rotated transmission by hand, everything<br />smooth, no noise.<br />Installed new heavy duty plate, rated for330 hp, fired her up.<br />Same noise at 750rpm stops at 1000rpm.<br /><br />Any ideas ?
