Our engineer Andy has just finished resolving a fuel control problem, and I figured I’d share it with you as it might help if you have a similar issue.
The problem was caused by a Woodward PSG governor fitted on a cruise vessel’s Daihatsu 6DL-20 generator engine.
The operator had tested the governor on board but found that when it reached the right temperature, the oil pressure was dropping. Once the governor had arrived in our workshop, we pretested it and found that when the oil temperature was at 138°F the oil pressure started to drop to less than 100psi instead of the 220psi it should have been.
Not only that, but the governor output lever could be moved by hand, indicating the governor was not developing enough power to operate the engine fuel racks correctly.
Why had this happened?
A combination of wear in the case and the internal components.
What the operator didn’t know was that the cases for these governors had been upgraded from aluminium to cast iron to reduce this problem and in fact, this model had been superseded by a cast iron version.
The problem with the old style aluminium case is that it wears quicker when carbon particles in the engine oil are picked up and act as an abrasive. Once the governor was overhauled and converted to a cast iron case, it was holding pressure – problem solved!
