Peter Caplen - MARINE DIESEL ENGINES: Care and Maintenance

First published in 2010 by

The Crowood Press Ltd

Ramsbury, Marlborough

Wiltshire SN8 2HR

www.crowood.com

This e-book edition first published in 2011

Peter Caplen 2010

All rights reserved. This e-book is copyright material and must not be copied, reproduced, transferred, distributed, leased, licensed or publicly performed or used in any way except as specifically permitted in writing by the publishers, as allowed under the terms and conditions under which it was purchased or as strictly permitted by applicable copyright law. Any unauthorised distribution or use of this text may be a direct infringement of the authors and publishers rights, and those responsible may be liable in law accordingly

ISBN 978 1 84797 353 5

Disclaimer

The author and the publisher do not accept any responsibility in any manner whatsoever for any error or omission, or any loss, damage, injury, adverse outcome or liability of any kind incurred as a result of the use of any of the information contained in this book, or reliance upon it.

Dedication

With love to Mumsie, still helping the old folks while spending the inheritance!

Originated by The Manila Typesetting Company

Printed and bound in India by Replika Press Ltd

Introduction

Despite recent changes in fuel taxation for privately owned boats, the diesel engine is still by far the most popular form of propulsive power for boats of all sizes, both power and sail. Although the loss of some taxation benefits has caused a rise in the price of diesel so it approaches that of petrol, there can be no doubt that diesel is still the best choice for boats. Gas oil, or red diesel, is the standard fuel for marine diesel engines; it is far less flammable than petrol, which is why it is unheard of for a diesel-powered craft to suffer from a fuel tank explosion something which cannot be said of petrol-engined craft, as the number of incidents, although fairly low, is depressingly regular.

Diesel engines are also twice as reliable as the petrol engine in theory at least because they have no electrical ignition system, which in the marine environment is always prone to suffer from the effects of the damp surroundings. However, in the last ten years or so electronically controlled diesels have to some extent lost this advantage. Then again, the sealed computer-based electronic systems used for controlling diesel engines are much less exposed than the petrol engine ignition system. The high levels of reliability of modern electronics mean that a complete breakdown is very unlikely, and this, coupled with the high efficiency and fuel economy of modern common-rail diesels, still gives the diesel engine a big economy edge over the petrol version.

These virtues make the diesel engine the favoured choice of the serious boat owner, who regards safety and reliability of paramount importance. Also to be considered is the fact that the economy of the diesel engine allows a vessel with a given fuel tank capacity to travel that much further when powered by diesel rather than petrol.

The easy availability of gas oil from boat yards and marinas makes refuelling more convenient; many yards are unable to stock petrol due to the stringent regulations covering the storage of petrol, which requires the additional heavy expense of installing underground tanks. The only area of the UK where petrol is readily available at nearly all marinas is the south coast, and in this area there are many more petrol-powered boats than in other areas. Moreover the fact that gas oil is still somewhat cheaper than petrol despite the loss in 2008 of the derogation allowing non-road diesel fuel to be taxed at a lower rate means that motor boating can still be enjoyed on a reasonable budget without too many worries about how wide the throttles are opened!

Many boat owners are still unfamiliar with the workings of the diesel engine, although with the prevalence of high efficiency diesels now commonly being used in cars, their mysteries are less puzzling. Anyone with a basic working knowledge of petrol engines will have a good basis for understanding the diesel, as there is little real difference between the two apart from the fuel system and the lack of an electrical ignition system. The mechanics of the diesel engine are basically identical to that of the petrol engine, and once the differences in fuelling are understood, they should not present any problems to the enthusiastic DIY owner.

This book explains everything the beginner needs to know to keep their boats diesel engines in good order, how to rectify simple faults, and how to save a great deal of cash on annual service costs. It will also be of benefit to the more knowledgeable owner who wants to fill in the gaps in their knowledge. It covers all the basic maintenance procedures, and also explains the workings of power-boosting equipment such as turbochargers, superchargers and intercoolers, and the way different types of marine cooling systems operate.

While there is a huge selection of practical material there is also plenty of detail about the history and development of the diesel engine. Hopefully this will give the owner a much better insight into (and interest in) their power unit than a straightforward workshop manual could provide. Unlike a workshop manual that explains no more than how to perform certain tasks, this book attempts to provide a basic understanding of the workings of the diesel engine; furthermore, while offering step-by-step instruction on practical maintenance procedures, it also explains exactly why each job is required.

Several sections concentrate on areas that many owners may not have considered of great importance. Fuel tanks are a case in point. Give a diesel engine a supply of clean, air-free fuel and even if it is almost totally clapped out it will probably still run; but introduce dirt or air into the fuel, and even a new engine will soon stop in protest. A clean fuel supply is the key to reliable running. Therefore, although these items may be unglamorous and unpleasant to deal with, they will ultimately reward the owner with a trouble-free seasons boating.

The largest chapters necessarily concentrate on the fuel, cooling and electrical systems, as these are where problems are most likely to occur. The cooling system will cause problems if it is not properly cleaned and maintained; in the worst case scenario the engine will overheat to the point of seizure, so it is most important to keep the cooling system in good order, yet this does not require any great degree of skill. Similarly some basic maintenance of the electrical system will ensure the engine starts when the key is turned, and continues running and charging the batteries until it is switched off.

Much of the practical content of this book is drawn from a long experience of keeping ailing diesel engines running on a minimal budget and with the minimum of facilities. This can be part of the pleasure of owning a vessel with inboard power, and for those who must work to a tight budget it is an almost essential skill!

It is a fact that a job completed by the owner, once the necessary knowledge has been acquired, will be of a higher standard than that performed by a service agent or boatyard as the owner knows only too well that if problems arise at sea it will be up to him alone to find the remedy, and that if a job is performed properly in the first place a problem will not arise later.

However, regardless of the financial considerations of the reader and whether or not they choose to have their annual maintenance performed professionally, self-sufficiency at sea and the ability to solve minor engine problems without having to alert the lifeboat is a part of good seamanship, and being able to rectify minor breakdowns should be a matter of pride. Your engine is your lifeline, and it is as well always to remember that the welfare state ends at the sea wall!