5 Common Problems with Marine Diesel Engines - and How to Overcome Them

Capul Northern Samar

Failure of a diesel engine is one of the leading explanations for lifeboat call outs, especially to fishing boats. Numerous instances of marine diesel engine malfunction are a result of a reasonably small number of errors therefore it’s normally possible to have the motor operating again within a short period of time. However, when establishing the cause of the problems it’s vital to look at problems in a systematic manner instead of immediately thinking you know what’s wrong, especially if you’re not quite as experienced with engines as you could be. For example, it’s necessary to start by checking whether there is enough fuel in the tank – it’s very easy to think that’s not the cause of problems but many fuel gauges are incorrectly calibrated, so examining with a dipstick or sight gauge is more precise. Here we discuss some of the common problems with marine engines, and how you can troubleshoot them to make your trips out less stressful and more fun.

1. Fuel Valve Malfunction/Fuel Leakage

Setbacks in the fuel system are also normally witnessed in the main engine. When there is a temperature change in one unit, the fuel system, and particularly the fuel valve needs to be examined. Pressure testing and revamping of fuel valve should to be performed. In diesel engines, the likelihoods of leakage from the pump seals eminent. Unregulated and improper treatment of the fuel valve can lead to cracks and leakages in high-pressure fuel pipe.

Solution: leakages in the main engine fuel oil system can be established from the “high pressure leak off tank” level and alarm; therefore maintenance of the oil systems combined with regular and thorough checks should avoid this.

2. Air Leakage

This is one of the most underestimated yet an almost commonplace problem associated with marine engines. The air system distributes air to different sections of the main engine. It is permanently in open state when the engine is in use. Small leakages are common and can be fixed by replacing or tightening the loose joints or pipes.

Solution: When the Engine is running and in good working condition it is hard to overhear any air leakage sound. The most effective way is to trace all the air lines and touch all the connections/ joints by hand to check for air leakage. The simplest way to trace air leakage is when there is a deliberate blackout. At this moment all the machinery will be in the “stop” position and a hissing noise (leakage sound) will be loud and clear.

3. Breakdown of Installed Gauges

Various systems of the main engine have parameter gauges. It is therefore vital to note down the readings in the logbook, and it is advised that boat owners take the local readings instead of the remote readings. Frequently engineers find that one or two gauges (pressure gauges, pyrometer, manometers etc.) installed in the main engine are not working. The cause for such circumstance can be due to connections, vibrations or loose parts.

Solution: It is always advice to do a routine check and replace all defective parameter gauges with new ones.

4. Defective Sensors and Alarms

The main engine and its systems are installed with various sensors, which gauge, determine, compute and transmit data to the alarm console. Owing to dynamics such as high temperature, humidity, high pressure, vibration, dust etc. these sensors can fail leading to erroneous alarms signals.
Solution: Routine inspections need to be done on all engine room sensors and alarms. Different main engine safety alarms need to be tried out at regular intervals and faults should be attended to straightaway.

5. Overheating

It’s imperative to be familiar with the elements of the cooling system on your boats engine. There is always interaction between the engine pistons and the high temperature and high-pressure area of the combustion chamber while the engine is in motion and the cooling system performs functions of pressure sealing and motion transmission to the crankshaft. In a marine diesel engine overheating can be triggered by various factors, some of which include:

  • Failure of the piston cooling system which leads to temperature rise
  • When the piston rings have inadequate clearance, crack and seize up, this will cause piston heating.
  • When the lubrication system of the cylinder jacket liner fails, this leads to an increase of heat due to friction.
  • A fault or failure of the rings can lead to leakage of combustion gases past the piston.
  • Poor combustion brought about by valve timing problems.

Solution: Most modern diesel marines are fitted with diagnostic equipment that helps make sense of all possible faults. It’s critical to examine the diagnostics thoroughly too. One of the most ignored and common critical errors is the failure to open the seacock when working on the engine.

All in all, most of the obvious ways to avoid these common problems are to ensure regular checks are done on all parts of your engine, and that logs are kept to measure performance. In addition to this, you should always look at purchasing the best parts for all parts of your engine. For example, Items like the PSS Shaft Seal mean you will likely see less leakage in general which will certainly help contribute to a smoother running engine. Combining good maintenance and regular checks with quality parts means the likelihood of problems with your engine will certainly be lessened, and you’ll be able to spend more time fishing.

NOTE: This post is from one of our contributors. Any views expressed do not necessarily reflect the views on www.pinoyadventurista.com.


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