I have a Volvo 2020B diesel in my Centaur yacht. Recently whilst out for a sail, although initially the engine ran well and at 2000 revs, after restarting on the way back the engine lacked power and would only achieve 1500 revs under power. It will rev over 3000 out of gear.There is blue smoke coming from the exhaust.I have cleaned soot and sludge from the exhaust elbow and the heat exchanger and changed the CAV filter, but no difference. Can anyone help diagnose the problem , please.
Les
Les