Suspecting air in the system a new lift pump, feed and return hoses, filter and all copper seals were replaced. This solved a leak around the lift pump but she still wouldn't rev. Pub engineers suggested the injectors needed an overhaul so in went two new injectors - at this point I found the original injectors had been incorrectly fitted but even so the symptoms persisted.

Then I noticed that there was an awful lot of crank case pressure which pointed to pistons, rings and perhaps the cylinder liners being worn. At this point I got some advice through the forums on http://boatdiesel.com/ which suggested that I should look at the exhaust manifold and port. On inspection the raw water cooled exhaust elbow had corroded away internally and allowed the sea water to get back up into the exhaust port resulting in very heavy corrosion. In fact there were large holes into the oil galleries on both sides of the port, which explained the crankcase pressure. Additionally where the port splits into two towards the valves they had become partially blocked with evaporate deposits with cylinder one exhausting through a tiny aperture of about 5mm diameter - it was amazing that this engine had started and run as well as it did..

After the cylinder head was removed the full horror became apparent and I started hunting for a used cylinder head (a new one was over £800). With no luck and the 2007 Spring Series a matter of weeks away I elected to try and get the head repaired. Local engineers had said no way could they weld cast iron, however Slinden Services Ltd (http://www.slinden.co.uk) came to the rescue with a fabulous service. In a matter of days the cylinder head was repaired and refitted.

What a difference! We can now hit 7 knots under power rather than wheezing up to 6 and the clouds of oil and soot pouring into the wake are gone.

During the strip I had also discovered that the front/left engine mount had sheared off allowing the engine to move out of alignment. I welded up the mount and with everything back in line we can now get back to the sailing...