instantly, or it may cut a few peculiar circles for a minute or two, but
don't get excited, look to the eccentrics at once for the trouble.

Your engine may however act very queer some time, and you may find the
eccentrics in their proper place. Then you must go into the steam chest
for the trouble. The valves in different engines are fastened on valve
rod in different ways. Some are held in place by jam nuts; a nut may
have worked loose, causing lost motion on the valve. This will make
your engine work badly. Other engines hold their valve by a clamp and
pin. This pin may work out, and when it does, your engine will stop,
very quickly to.

If you thoroughly understand the working of the steam, you can readily
detect any defect in your cylinder or steam chest, by the use of your
cylinder cocks. Suppose we try them once. Turn your engine on the
forward center, now open the cocks and give the engine the steam
pressure. If the steam blows out at the forward cock we know that we
have sufficient lead. Now turn back to the back center, and give it
steam again; if it blows out the same at this cock, we can conclude that
our valve is in its proper position. Now reverse the engine and do the
same thing; if the cocks act the same, we know we are right. Suppose
the steam blows out of one cock all right, and when we bring the engine
to the other center no steam escapes from this cock, then we know that
something is wrong with the valve, and if the eccentrics are in their
proper position the trouble must be in the steam chest, and if we open
it up we will find the valve has become loosened on the rod. Again
suppose we put the engine on a center, and on giving it steam, we find
the steam blowing out at both cocks.

Now what is the trouble, for no engine in perfect shape will allow the