I have the newer fuel pump on my 912uls and I tested gravity fuel flow thru the fuel pump that was not running but was in good condition. Flow thru the pump was definitely less than when measured with the line disconnected just before the pump. I have no filters or shut-off valves in the lines from tanks to header; one shut-off in the console; one inline filter just before the fuel pump; no electric boost pump. A non-running pump is a definite restriction and I would think probably would prevent WOT operation, but would still allow the engine to run continuosly at a lower throttle setting. Of course this could all change if the pump were damaged and loose debris causes additional blockages.