I blamed the boots I had on and then decided to find the cause today.
Felt the cable from the bulkhead to the pedal ( brave soul or just stupid ? ) feeling for broken cable strands. None found !
Into the engine bay and started to look at the cable at the pump. OK .
And then noticed the black plastic piece ( joins the cable to the pump lever ) was not returning to its proper position.
Found that the pivot bolt into the plastic arm was extremely stiff ( threaded bolt into plastic arm ). Dismantle, clean all parts,reassemble and then put it back onto the motor and roadtest.
Job well done !