As a marine loss adjustor and coastguard NZ senior master, Paul Field has a wealth of boating knowledge. Here, he shares some advice about engine maintenance.

As my capacity as both a Marine Loss Adjustor and a Coastguard New Zealand search and rescue volunteer, there are many common mechanically related issues and failures that I frequently see.

Componentry failures can often be more significant when regular maintenance and servicing isn’t attended to proactively and issues aren’t caught early. However, with rising cost-of-living expenses, and on-going supply chain and freight issues still impacting the availability of parts, some boat owners might not be staying up to date with their regular vessel servicing and maintenance. Ignoring regular maintenance and servicing often leads to detrimental impacts, whether that be preventable mechanical failures or larger repair costs in the long run.

Maintenance and servicing

As vessel owners we need to be fully aware of our responsibilities when it comes to maintaining and servicing our vessels. Open and ongoing communication with trusted service agents is always encouraged. Have them regularly look at those vessel components that are subject to wear and tear and review your craft’s drive line in its entirety to schedule regular upkeep. Periodically, this will require more expensive servicing when major items become due for replacement. But replacing these items when required is an important part of responsible vessel ownership.

Keeping a digital or physical folder with all your vessel service records is also a good idea. Having a clear record of works undertaken on your craft will also come in handy should you decide to sell your vessel and will go a long way to satisfying potential buyers.

Here we will look at some of the common engine and mechanical failure issues. Of course, this article isn’t intended to be an exhaustive list of all mechanical service items you need to be aware of with your vessel, and we would always encourage you to have regular dialogue with your trusted service agents.

Engine control units

Most modern engines have computer engine control units (ECUs). These often control such things as fuel flow, water flow, operating temperatures and rev ranges. They can also record operation of the unit, along with any number of failure warnings and alarm triggers and safe modes of operation. All of this is designed to try and prevent more major damage.

The recorded data log assists marine service agents in quickly determining the cause of a failure and or where to start the diagnosis of damage. Having a long data record of operation assists in identifying any ongoing trends and can help to validate a sudden failure.

Common outboard engine issues

There are a variety of common failures which we tend to see each season. Unfortunately, each of the failure types could largely be prevented by way of simple regular servicing. Water pump and water pump impellors provide a source of cooling raw water flow through the engine to prevent the unit from overheating. Aside from being monitored through various sensors an outboard will have a “Tell tail”, which shows there is water flow. What is important to note however is that this water “Tell tail” doesn’t necessarily confirm the correct volume of water is flowing, only that there is water flow through the system. Rubber water pump impellors need regular replacement due to blade wear and perishing, often found to be a common source of overheating issues. We commonly see gearbox oil and propeller shaft seal failures associated with mono or braid fishing line entanglement. A compromised shaft seal can allow the escape of gearbox oil, hence it is important to check around the unit prior to, and following use, to ensure there is no weeping of oil or any fishing line wrapped around the propeller shaft/propeller hub.

Regular gearbox oil checks are important as early detection of any emulsified (milky) coloured oil is an indication of water presence. Left in situ, water presence will compromise gearbox internals and can result in costly internal gearbox failures. The carrier nut threads into the gearbox barrel in the gearcase and is commonly associated with cracked or fractured gear casings. Regular removal and cleaning of threads along with a grease and reassembly is an easy and inexpensive way to ensure that any confined electrolysis between the metals doesn’t occur, or is quickly identified and addressed preventing the forced expansion and final fracture of cast casings. Electrical shorting of wiring or similar ignition type damage is another relatively easy and inexpensive preventable issue.

Regular inspections of and quick attendance to any chafing or connection compromise can prevent a fire within the electrical system which, more concerningly, is close to fuel sources. We recommend regular inspection of fuel lines for chafing and or perishing is undertaken along with regular checks of all hose clips to ensure they are tight and secure. Not only does this prevent air ingestion to the fuel system, it also prevents fuel and vapour escape which are highly flammable.

Common inboard engine issues

Many of the easily identifiable issues mentioned for outboard engines are equally applicable to inboard engines although we note some more particular areas to keep a watchful eye on.

Again, we note the introduction of computer ECUs on more modern engines play a significant part in determining any impending failures or past events and can greatly assist owners, service engineers, and assessors alike in confirming the sudden nature of a failure or a previously developing situation.

With both diesel and petrol inboard engines in the market, the regular checking of fuel supply lines, connections and filters with scheduled replacement greatly limits the ability of a system to experience compromise or provide for a fire hazard in craft. We have seen many cases of diesel bug contamination which occurs over an extended period and could have been arrested if only for regular filter changes, regular Biocide use and fuel filter bulb inspection. Water in the fuel is a trigger with diesel bug as this provides the cultivating environment for growth.

Regular inspection can determine the presence of water before it gets to a height able to be ingested into an engine. Be conscious of the location of fuelling points on your craft such as low-lying fillers and especially check rubber O Rings on fuel caps designed to provide a seal and prevent ingress. The regular check of fuel filter water separators can alert to the presence of water prior to an ingestion situation. In many designed engines, oil flow is provided by way of a mechanical oil pump. Regular functionality testing and oil changes with further scheduled oil filter changes will ensure your oil system is clear to function normally.

We regularly attend overheated engines resulting from oil flow blockages, more commonly in older generation engines where there has been no maintenance. Without clear oil flow the effect on an operating engine can be sudden and catastrophic. Equally it is important to regularly check gearbox oil and engine oil for emulsification from water presence. The most common source of contamination we generally see is from oil coolers which rely on coolant water circulating around sealed oil chambers where oil is pumped through. An internally corroded cooler can allow water into the system and oil to escape the pressurised unit. Regular descaling and purging of coolers can prevent corrosion compromise and identify issues prior to final failure.

Regular checking of all connecting raw water hoses and fastenings to and from skin fittings, strainers and water pump inspection can drastically reduce the potential for hose compromise or detachment. Many a vessel has been prevented from sinking due to simply shutting down the engine and by association the cessation of pumping water into a vessel.

Wet exhaust systems are a longer-term scheduled item to check and can prevent the ingestion of water into engines from the early identification of internal corrosion and rust. The check of a wet exhaust system is a more costly aspect to servicing but necessary to ensure continued reliable use of your engine.

Regular servicing is a must

While it may seem like there are many things that can cause engine issues which could potentially lead to engine failure, it is important to remember that most of the items discussed in this article are relatively easy for a service agent to check and mitigate against.

Making sure you have open and ongoing communication with your service providers is key. It’s important to establish a regular scheduled maintenance regime, which takes into consideration how you use your boat, how often you go boating and the age of your vessel.

A significant part of responsible vessel ownership is factoring in the harshness of the marine environment. There are so many elements all trying to damage your vessel, by way of factors such as acidic water content, UV light, corrosion and rust to name but a few.

As vessel owners it’s important we do our utmost to minimise the effects of the marine environment on our vessels. However, we also need to recognise that even with regular maintenance, all vessel components can suffer wear and tear. Vessel components don’t have an infinite lifespan. Which is why as vessel owners we need to be proactive and organised with our maintenance and servicing regimes, to try and avoid failure incidences and stay safe on the water.

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