frequently, say, every eight or ten runs, to clean the fine-wire mesh. Sometimes, when oil is mixed with the gasoline in the tank, the fine mesh of the strainer gathers a gum-like substance that in time clogs enough to stop the flow of fuel. The catch of water may easily be run off by a turn of the cock at the bottom of the strainer. Frequent cleaning of the strainer will prevent the corroding of its screens. With all precaution and care the strainer will occasionaly become damaged; when it does a short piece of pipe should be inserted in the place occupied by the strainer. If the gasoline is properly strained before being poured into the tank, the probability is that the flow will continue for many trips without trouble.

35. Placing the Pipe Line.-The pipe line should not be laid where it can be trodden upon, as it may be flattened, or broken, for the finely drawn pipe is fairly brittle. If necessary to bring it across the floor it should be run in a corner or covered the same as electric wires are covered when on the outside of walls. Leaks in the line can easily be treated with shellac, the best shellac being that which has coagulated a little in the bottom of a bottle, or box.

The pipe line should be of copper, and should not be run under floors, or in out-of-the-way or inaccessible places. It should be renewed every 2 or 3 years, because it crystallizes under the constant vibration. It also may corrode in spots under the action of salt water. If it clogs, the fuel should be shut off and the pipe disconnected. It can then be blown out with an air pump, or a long wire can be run through it. It is well to have all pipes as short as possible. Ground joints in the line are more easily handled than threaded ones. Ground joints are smooth-ended and are drawn together with the use of box-like nuts.

A rubber section should never be installed in the gasoline pipe line, because gasoline is a solvent for rubber and the rubber will be carried into the piston and rings. The gasoline supply pipe should be of good size so that it will not become obstructed easily.

36. Running With Broken Pipe.-In case the gasoline pipe line becomes broken, the engine can be kept running by

pouring gasoline into the length of pipe that is attached to the carbureter. The gasoline can be poured into the pipe by using a funnel or by using the long spout of an oil can that has been cleaned out with gasoline. All that is necessary is to keep the length of pipe filled by drawing fuel from the tank and pouring it into the funnel or oil-can spout as the engine uses it.

LOCATION OF CONTROL LEVERS

CONTROL LEVERS ON ENGINE

37. In many boats, especially the smaller and less expensive ones, the levers for controlling the time of ignition and the

throttle valve are located on some part of the engine within easy reach of the operator. In Fig. 5, the control levers are

shown located on the engine itself. The timer is operated by the lever a. Moving this lever in one direction advances the spark, and moving it in the opposite direction retards the spark. The direction in which to move this lever in order to secure the desired results is given for any particular engine in the instructions that are sent out by the maker. The lever b operates the throttle valve of the carbureter c through the rod d. The direction to move this lever in order to open or close the valve is also given in the maker's instructions.

38. The control levers are not always located in the exact positions shown but they are usually close to each other at the forward end of the engine. When one does not know the direction in which to move them, and the directions of the maker are not at hand, this information may sometimes be obtained by inspection. For instance, in order to advance the spark, it is necessary to rotate the movable part of the timer in a direction opposite to that from which the timer rotor is turning. In like manner, the spark is retarded, or made to occur later, by moving the lever in the same direction in which the rotor turns. These directions apply to timers, but in the case of magneto ignition, where the spark time is varied by moving some part of the magneto interrupter, it is more difficult to determine the direction in which to rotate the lever. One should not attempt to start an engine until he is sure that the spark is retarded; otherwise, serious injury might result.

In some makes of carbureters it is possible to tell by inspection when the throttle valve is open and when it is closed. However, by attempting to start the engine with the throttle lever in different positions, the open and closed positions may be ascertained.

It is always the best plan, especially for the novice, to follow the maker's instructions and thus clear away any doubt as to how to obtain the desired results.

BULKHEAD CONTROL

39. In a large number of boats, the throttle valve and timer are operated from levers located on the bulkhead, forming the bulkhead control. This form of control is made possible in the modern boat with its engine well forwards and the bulkhead between the motor and the helmsman. The switches and push buttons are fastened on the bulkhead within easy reach of the operator and are wired to the battery or magneto, or to both where a double or dual system of ignition

is found.

FIG. 6

The levers are sometimes fastened to the bulkhead in the place most convenient to the steering wheel and a system of rods and levers lead to the timer or magneto and to the carbureter, or they may be located on top the steering wheel. With the latter arrangement, the control rods are brought up through the hollow steering-wheel shaft. Sometimes the levers are located under the steering wheel.

40. In Fig. 6 is shown a bulkhead control arrangement in which the control levers are located on the steering wheel.

The throttle lever a and the spark lever b are arranged on a quadrant c, around which they may be moved. They are connected to the timing device and the carbureter by means of rods passing down through the shaft d of the steering wheel. The switch e and gauges ƒ and g are located on the bulkhead within easy reach of the steering wheel. A starting crank for the purpose of turning the engine over by hand when starting, is located at h, and the reversing-gear lever at i. This is a very convenient arrangement and one that is coming more and more into use. The bulkhead control is also sometimes

throttle valve and timer by means of the rods and bell-cranks as shown. In this construction, the rods pass from the bellcranks, through the bulkhead d, directly to the devices they are meant to operate.

Another system of levers and rods is shown in Fig. 8, where the rod a from the lever b passes through the bulkhead to a bell-crank c. From this bell-crank a second rod d passes to the throttle valve or timer. In both Figs. 7 and 8 the control levers are located directly on the bulkhead and not on the steering wheel.