The unit is mixing oil and water in the sump and we suspect this is coming from water getting into the cylinders due to an incorrect raw water pump being used. I suspect this has caused a hydraulic lock at some stage and suspect a slightly bent conrod as the unit runs rough and is difficult to start. There are two options 1 Replace the unit 2 Strip and rebuild the existing unit We can fit a new raw water pump for now and change oil and filters and see how she runs The raw water pump circulates fresh water through the closed cooling system on the genset and then is fed into the exhaust which is then fed overboard. A electric pump was fitted in place of this pump which also is used for deck washing etc. This is where the problem is . Hopefully a conrod is not bent - any suggestions to see our way forward?