I have a motor Volvo Penta AQD 41A in my boat, and now I have a problem that I don't get to identify. - The motor usually works, meantime after some hours of use, it expels the whole lubricating oil through the breath filter. I made the test of compression emission opening the cover where the oil is put, and I didn't notice any compression emission. I would like somebody to guide myself to I respect, because several mechanics that I consulted myself didn't give a satisfactory answer. The apparent causes would be rest in the pistons, but that is not true because the motor is not with the level of the low oil.
Thanks Fernando