Great Mr. Oli, Pleased to see your quick reply for my messages-
1. Yes but if feet are deteriorated just in one end it may get a waggling movement. So yes that is to make sure no tilting axial resonance is the problem.
Ans: Very correct. But radial vibrations and Alternator end Axial vibrations are in satisfactory levels.
2. yes it is a abnormal nice looking vessel. However not all oil problems are showing external in this case from last year it was parts of a broken gear that showed up in the oil. It that case nobody did look at the oil, they just swapped filters and oil so it happens.
So next is if you did look at the coupling but normally it also should get some indications in the generator but there are exceptions. Some generators have a axial bearing in the free end so the generator shaft expands in to the gearbox or diesel when getting warm and OEM claim it is supposed to be like that and it require larger axial play in the coupling to take care of that or you get axial problems in the gearbox/diesel.
Ans: At next opportunity we will explore those issues. Normally Lube oil is the major issue and now present engines are running with VLSHFO (very Low Sulphur Heavy Fuel oil) and This company normally take care of such issues regularly. However, we should get an opportunity to identify the engine performance too.
3. So yes in the end it may be a cylinder unbalance maybe, just to check the obvious I take a vibration reading at all injectors to sort out if there are any that is different then it is worth to check them.
Ans: We should study something more on this issue, this is not only the company but many YANMAR diesel generators are exposed to this type of Axial Vibration problem.
We will appreciate if you also can explore from your end to trace the real issues.