General maintenance

This is not the place for detailed instructions on stripping and rebuilding an engine. However, anyone can change the engine and gearbox oil and do a few other simple maintenance jobs. A diesel engine is a case where some owner-maintenance will make the difference to the efficiency and cost– and it is not that difficult. Let’s look at some of the basics:

Oil changes (pretty much applies to all engines)

• Always drain the motor and gearbox when the oil is warm
• Always use a new filter - Some older engines actually do not have one – they use a filter plate instead. On a daily use basis, rotate the key on the plate, but at service time, it never hurts to remove the filter and wash the plate in kero.
• Always use a large drain pan and take the old oil to a recycling centre
• Wear gloves (rubber, nitrile, etc.) while doing ANY maintenance on diesels. There is a LOT of potential for skin problems from dirty oil
• When finished DO NOT over-tighten the drain plug OR the oil filter!
• DO NOT forget to replace the oil before starting - Add just a bit less than the specified amount of oil, start the engine, let it idle for a little while, shut it off, let the oil drain back to the pan and then adjust the level. DO NOT OVERFILL

Fuel system check

In a petrol engine, you must ensure nothing leaks, keep everything clean, change the spark plugs and generally ensure everything is tight and in good order. Diesels though are absolutely reliant on clean fuel without water or other contamination.

• Drain the water-trap filter regularly
• Check all fuel lines for fraying or leaking and replace if necessary.
• Keep the fuel tank as full as possible
• Add a biocide to the tank – especially if it is to be left unused for any length of time
• Do NOT meddle with the governor, pump or injectors unless you actually know what you are doing!

Cooling system check

The most obvious and essential maintenance consists of looking carefully at the hoses especially where they are jointed to a flange or seacock. If in doubt, replace any suspect hose.. Please be warned – failure to do this could cook the engine OR even sink the vessel. Hoses MUST be replaced with the correct reinforced hose material. This is not a place to save money.

The same applies to the drive belt – it should always be free of cracks and be tight enough to resist movement by hand. The adjustment us usually just two or maybe three bolts on the water pump. Loosen them, lever the pump to tighten (but not over-tighten) the belt. Then retighten the bolts.

You should also know how to change the impeller inside the water pump.- a simple job requiring nothing more than removing the drive belt and undoing a few screws (or bolts). Always carry a spare impeller on board. After a split/loose hose or blocked intake, this is probably the most common cause of overheating

An excellent article is available at: http://www.catalina36.org/articles/maintenance/Oil&FilterChange.htm

Gearbox

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Shaft alignment is far more simple than generally believed and is well within the capability of the Handymariner. The following extract from Marine Engineer World explains the technique:

Offset Alignment
The radial alignment is checked using a straight edge ruler. By placing the ruler across the coupling halves at the top, bottom and both sides any gaps between the 2 coupling halves will indicate that the shaft is offset slightly. The misalignment can be corrected by shifting the motor or by putting shims to raise up the motor or drive.

Angular alignment
By inserting a feeler gauge between the coupling faces and rotate both coupling halves simultaneously we can check whether the shafts have any angular displacement between them. The feeler gauge readings at checked at four points on the shaft coupling. Again the alignment is corrected by shimming.

Everything should be bolted solidly to the base after finalizing the alignment positions