1) Recognition of the real problem. And, elimination of secondary damages caused by a first strike (damage).
a. what happened?
b. when start?
c. from which part of engine does it start?
2) What is a real "trigger" of the problem and/or what is the most possible cause among many possibilities?
3) How to remove "trigger" from the main engine suffered by it.
4) What kind of pre-caution measure(s) to be taken. Additional measures used to applies, in order to assure the safer operation on future.
4. Typical characteristics indicates the possibilities of difficulties caused by fuel oil.
In the following cases, we used to say that the quality of fuel oil is one of the possible causes of difficulties.
1) The problem happened almost all the cyl. units and at a same time.
2) A good running behavior was confirmed, before the problem was noticed.
3) The surface observation during and/or shortly after the problem happened used to give an important sign of real cause. Especially, in the case of an abrasive wear due to cat-fines, the surface condition (replica) is an evidence preserving the real cause like "a finger print".
According to our experiences, it is not always observed that the chemical analysis show high content of Al+Si and/or mixing of miscellaneous substances. In many cases, contrary to say, all the properties are within "standard". Therefore, it is very important to collect the fuel oil samples and replicas when difficulties are on the way and/or finished shortly before. Unless, "secondary damages" were prevailing on the first and real damage.
5. The proposals as a service engineer of engine builder for the quality control of fuel oil for slow speed marine diesel engines.
Ship managers does not always chemically analyze the quality of bunker fuel at special laboratories before use. In many cases, fuel oil specification such as specific gravity, viscosity and sometimes sulfur and water content are described in the bunker receipt, and these figures are used by the operators to set the heating up temperature and decide how to pre-treat the newly bunkered fuel oil before use. However, one bunker supplier said "the figures in a bunker receipt was only a reference".
Moreover, big difficulties is expected in combustion character among the similar quality of fuel oils in the market, because fuel oil is not distilled fuel oil but residual oils commonly.
