Engine work and more.

Fuel Filter Assembly.

Scanning through the workshop manual for the engine I found that the thermostat has a life of 2,000 hours (it is not on the service schedule in the operations manual!) so it was due and quite possibly overdue for replacement. But first up was the service and inspection, that all went fine until the thread on the bleed screw on the fuel filter gave up the ghost, it has always been problematical with a tendency to leak and now it would not seal with the normal copper washer and it was rather iffy without. I was unsure about how good the thread in the filter assembly was so rather than faff about finding the right bleed screw, with the entire assembly complete with a filter at £80 I opted for that.

Fitting was straight forward and I had previously invested in a large assorted pack of copper crush washers so there was no need to hunt down the right size.

Thermostat & hose replacement.

I had already replaced all of the hoses except the short piece to the thermostat that was probably original to the engine but I found a rub on the hose from the seacock to the water filter were it was too close to the engine sump being a little too long. With hose not costing that much and coming in multiples of one metre I decided I might as well replace more and opted for a premium silicone at £10 per metres incl postage.

Fuel filter top left, thermostat housing top centre between the two
pieces of red hose, the lower one is the bypass hose.

It was a good job that I decided to change the thermostat because I found that the bypass hose and the outlet from the cylinder intake coupling was completely blocked with salt; had the thermostat ever been changed? It certainly had not been since the engine was resprayed after a "major service" in 2014. 

The engine is not going to overheat because of this, to the contrary the thermostat when fully open with the water temperature at 52°C  blocks the bypass to force all of the cooling water through the block and cylinder head, but it does mean that the engine would be slow to warm up, the thermostat does not start to restrict water through the bypass until the water in the outlet is 42°C so for an extended period it would have been running even cooler than normal for a raw water cooled engine that already runs cool compared to the heat exchanger equipped fresh water cooled version. 

That is probably the reason that the engine has smoked a little in the early morning at relatively low power. After clearing out the coupling, replacing the thermostat and hose the engine smoked not at all on a particularly chilly day, hopefully it will not do so when under cruising load.

to be continued.