Kings Marine's Top 5 Marine Breakdowns

In a straw poll of customers visiting the shop, the most common cause of boat power breakdown's was felt to be mechanical. In reality, the mechanical components of a boat and its engine are far from the most common to cause problems. We've drawn on over ten years of marine maintenance to bring you what we consider to be the top 5 reasons for a power boat to break down.

1 . Contaminated Fuel

Around 80% of engine running problems that we see are due to stale or contaminated fuel. One customer recently purchased an engine from us, fitted it to his boat and was most put out when it ran like a 'bag of nails" as he put it. When we'd had a chance to drain the fuel system and let it sit in a glass container for a while, the brown sludge separated out from the brown, stale petrol. One of the mechanics suggested that maybe the fuel tank was used for nail storage. A good flush through with fresh fuel and the engine ran just perfectly.

How does water get into the fuel?

Sometimes is can be through poorly maintained waterside fuel depots. We have had cases where the boat owner has simply left the fuel cap off after refuelling.

More usually it forms from condensation in the tank through the colder months of the year. The area above the fuel in the tank is open to the atmosphere through the fuel tank breather pipework. As the air is warmed and cooled throught the day so air is drawn in and expelled from the tank. Some amount of fresh air is therefore above the fuel. The cold of the night cools the tank and the water vapour in the air forms condensation on the inside of the tank. The condensation falls down the sides of the tank and sits under the fuel where it is sealed from the outside world and cannot evaporate as daylight and warmth returns. Little by little, night by night more condensation is formed and builds up under the fuel.

So how do you know you've got a problem with water contamination in the fuel?

There's a good chance it won't be noticed for some years as it will sit below the level of the fuel pick-up pipe in the tank. However, one day when the boat is rocking more than usual, or the sea is rougher, the engine will start to pick up small amounts of water from the tank. It'll cough a little now and again, then start to misfire. If there's enough water picked up, it'll stop and won't restart without having the fuel system drained of water.

So how do you avoid these problems?

Firstly, always fill up from a fuel depot with a good throughput of customers. Fuel that has been sat for a long while in poorly maintained tanks is likely to include contaminates such as water or rust.

A water seperating fuel filter is a valuable addition to any boat fuel system. These are about a pint in size and fix in the pipework between the tank and the engine. In some cases the fuel filter will have a transparent bowl attached making it easy to see any rust or water. It's a little more difficult to fit these filters on inland waterways as the safety regulations prevent the more common plastic bowled filters from being used. However, the fuel filter is the first place we check when poor or erratic engine performance is a problem. We'll poor the fuel into a glass container and let it settle for a while. The water will be obvious.

With a half empty fuel tank, condensation will always form to some extent, even in the summer months. However, in the summer months the quantity is going to be negligible. Towards the cooler months, condensation can be minimised by keeping the fuel tank full. Fuel does 'go off' after a few months, so it is important to treat it with a fuel stabiliser too.

2. Flat Battery

Second most popular on our list is the inability to start an engine because of a flat battery. Push-starting a boat is, I'm sure you'll appreciate, a wet and somewhat implausible proposition. Here at Kings, we make great use of a what we refer to as 'jump-pack'. This is a remarkably small and portable battery in a plastic case with an option to be charged either from your car, or from the mains at home. Many new boat owners here in the yard specify one as part of the new boat kit. They'll easily start a well maintained engine that is simply short of battery power, however you can't really expect them to start an engine with a problem that requires many repeated attempts with the starter.

So how do you avoid a flat battery?

Batteries can be flat for many reasons, some that we've been made aware of are.

- A leaky cover can mean that the bilge pump is continually operating when it rains.

- The children awoke during the night and couldn't sleep without a light on. Both batteries can be flattened by old fashioned, power hungry filament bulbs.

- For marina moored boats with shore power, the battery charger or a fuse often fails. Mains power on boats is unreliable at best. Damp conditions and the overriding need for safety can mean that sensitive shore-power trip fuses can isolate power to the boat at any time. Marine battery chargers have a hard life in the cold and damp and we replace a handful of corroded chargers each year.

- It isn't flat at all.

You've just tried the blower fan/bilge pump/cabin lights and they don't work, so the logical conclusion is that the battery must be flat. It might just be that the bit of kit you've tried has a blown fuse. We've had three of these in the last two weeks, each time the owner had not even tried to start the engine, assuming that if the blower fan/bilge pump/cabin lights didn't work, then the engine wouldn't either.

- The battery has been left all winter and has discharged itself.

The common lead acid batteries will loose charge over time, especially as they get older. As batteries grow older so they 'sulphate', leading to a lack of ability to retain as much charge as they should. Their capacity falls. It'll probably remain unnoticed while there is enough power for an overnight stay and to restart the engines in the morning. You'll find that one morning the starting will be slightly sluggish and you'll take a note not to use quite so many cabin lights the next evening. When you get to the stage of washing up after supper by candlelight, you know it's time to get the batteries capacity checked.

Battery storage over winter affects working life significantly. Ideally batteries should be removed to somewhere frost-free and be trickle charged once a month. If you decide to do this, remember if the boat over-winters in the water, that any water ingress into the boat from rain, or a failing outdrive seal will not be automatically pumped out by the bilge pump. Checking the boat on a regular basis is essential.

3. Operator Headspace Error

Borrowed from the computer industry where the help desk were quite often inundated with what they referred to as 'Operator Headspace Error'. A term used to reflect the slightly arrogant nature of some computer techies to people having what they regard as simple problems with their computers.

However if someone has a problem, then by definition is isn't simple. If the user can't cure it, then the correct advice is needed to solve it. We'd like to think that's one of the reasons we're here.

Usually in this case, no matter what the boat owner has tried, the engine is simply spinning over and won't start. Or... even more frustratingly, it starts and then immediately stops. There are so many safety interupts on new engines to stop you starting the engine whilst in gear, or without the kill-cord fitted, that it is easy to overlook the simple. Some inboard engines will start for a few seconds without a kill cord, giving the impression that all is well with the kill-cord and other safety cut-outs.

The general rule to prevent this problem is to start again from the very basic. It might appear daft, but maybe even go as far as to step off the boat and re-board, going through all the usual checks and switches on the way. Doube check them as you go, and give the engine control a good wiggle to check neutral is selected and settled. We've been called out to three problems like this over the summer.

4. Lack of Maintenance/Lack of Use

Over a summer like we've had this year, many boats have only been sporadically used, if at all. The rain that persisted from the start to the end of the school holidays only served to dampen everyone's enthusiasm for messing about in boats. We're now beginning to see the results of this lack of use as we start the round of servicing, winterisation and de-commissioning for the winter.

We're finding that control and steering cables are stiffer than they should be, which an amount of exercise cures. Switch contacts also suffer when not used with the result that their reliabilty becomes a lottery. Depending on manufacture some switches last better than others. Modern ignition switches are well sealed against the environment, but older or worn examples have brittle or worn seals that let the moisture attack the contacts. Secondary switches, such as those used for cabin lights are often not as well sealed and can fail completelty. We've been replacing a fair few navigation light swicthes on some makes of boat for just this reason.

When a switch is used, the contacts inside 'wipe' across each other. The wiping action cleans the contacts, extending the life and reliability of the switch.

Damp and cold engine bays also encourage corrosion problems in electrical connections and switches. Older boats will have mechanical ignition points that won't like the damp too. Ignition systems on petrol boats generally don't take kindly to dust and the moisture that is held by the dust. If an engine fails to start, or runs roughly, one of the things to check is the cleanliness of the igniton parts and also the inside of the distributor cap.

Even if a boat is not used, it is essential that maintenance programs are adhered to. Not only will they ensure that your warranty is validated, but build reliability and keep costs low by ensuring any problems are picked up and cured whilst they are still small.

5. Electrical or Electronic Failures

To some extent, engine electrical and electronic failures can be caused by lack of proper maintenance and storage as mentioned before. Of course, with today's highly advanced engine computer systems, mated to a plethora of sensors, there is great scope for a component failure to bring about engine problems. Even the latest ranges of diesel engines have computer controlled fuel injection systems.

Over the last few weeks we have come across three computer or igntion system failures. In two cases, there was damp ingress to the ignition system that had resulted in corrosion in the unit. In the third case, it was simply an electronic component failure after ten years of use.

Such problems of electronic component failure are thankfully uncommon. They are sometimes difficult to diagnose on the more complex engines, such as the way too complex HPDI two-strokes, but in many cases there is simply nothing you can do, beyond correct storage and servicing to keep corrosion at bay, to prevent electronic component failure. In such cases you may well have to resort to the Secondary Means Of Propulsion you have on board. As if to complete the circle, if it's an engine, make sure it has it's own clean fuel supply!

Advice?

Kings Marine have been providing marine service, maintenance and advice from the site here in Chertsey for over 10 years. If you have a problem with your boat, send us an email or give us a call, we'll be pleased to help.