PREFACE This Reference Book has been prepared mainly from a series of notes compiled by J. L. Hobbs, who has had a long and varied experience with the care and repair of gas and oil engines. Much valuable information has also been abstracted from the publications of various manufacturers of gas and oil engines, especially from material obtained through the courtesy of the International Harvester Company of America, the De Vergne Machine Company, and the West- ingliouse Machine Company. INTRODUCTION INTERNAL COMBUSTION ENGINES While there are a great many books dealing with the theory and design of gas engines, as well as their operation, there has been a great lack of information relating to the care and repair of gas engines. Those that have devoted themselves to the work of gas engine repair have Iargely obtained their knowledge of the subject by practical experience. The author of this treatise on gas engine repairs has been forced to obtain his knowledge in this way, which, after aIl, Is the best, although it is often a slow, expensive and difficult one. In order to make it easier for others who are engaged in this work or who Intorid to enter into this field, the most important points relative to the care and repair of gas engines have been put down in the folIowing chapters, thereby providing a means by which others may find it easier to become familiar with this subject. There has always been an air of mystery surrounding the gas engine. Often everything seems to be in the best condition and yet the engine may refuse to start or may not develop its rated power. The fact is, however, that, as a rule, the troubles likely to arise are easily detected, providing one has the knowledge to look for the causes of dificulties at such points where they may arise. Under the four heads of Compression, Carburetion, Ignitiori and Lubrication, practically all of the ordinary difficulties that arise in gas engine operation are dealt with special chapters on cooling systems and on installation have been added, the latter giving information to ouriers and others to whom the installation of a gas engine plant may be entrusted...