I have recently winterised these engines but the engine block drain port are blocked. The block drains from a 'Y' fitting fitted to the block, with a drain plug in one side of the 'Y' and the engine knock sensor on the other. I've tried to clear the blockage with some copper wire but it won't clear. The engine manual states that this 'Y' piece must not be disturbed as it will upset the sensor.
My question is has anyone had the same problem and remove this 'Y' to clear the blockage. Assuming the sensor is vibration sensor tuned to detect the engine knocking, I can see why careful removal and refitting would be a problem.
I'm going to try and clear the blockage by blowing it through with compressed air which I'm hoping will clear the blockage.