Knocks or pounds of follower plate are generally caused by dirt accumulating in the hole, which will not allow the bolts to enter far enough to take up the lost motion of the plate, or the bolts may be too long. To remedy this, remove the accumulation of dirt from the hole, or shorten the bolts.
The knocks or pounds in main crank shaft, if caused by the bearings being worn oval or out of round, may be remedied by removing the shaft; true it up in a lathe, and refit or re-babbitt the boxes.
The knock or pound in eccentrics is generally caused by the eccentric straps being too loose upon the eccentrics, which can be remedied by reducing the liners in the straps to allow them to fit perfectly.
The knock or pound in slide valve caused by being improperly set, may be remedied by taking off the steam chest bonnet and re-adjusting the valve so as to give the same amount of lead at each end of stroke. This being done, and the valve well proportioned and the connections properly fitted, there should be no knocks or pounds from this cause.
The knock or pound in cylinder caused by shoulders being worn in it, can be remedied by re-boring the cylinder, being sure to make the counter bore of sufficient depth to allow the piston rings to overlap them at the end of each stroke.
The knock or pound on guides caused by shoulders being worn on them, is remedied by planing the guides and making the shoe slides of sufficient length to overlap the guides at either end when crank is on the center.
The knock or pound caused by the cross-head slides not fitting the guides properly, may be remedied by adjusting them both top and bottom to fit the guides closely, being careful not to get them too tight, which causes undue wear and strain upon the frame.
The knock or pound caused by wrist-pin or crank-pin becoming worn flat or oval, may be remedied by filing them perfectly round.
The knock or pound caused by the piston leaking, which causes cushioning, can be remedied only by having a tight piston.
The knock or pound caused by the driving pulley key being loose, can be remedied by driving the key in its seat; or if a defective key, replace by a new one perfectly fitted.
If the knocks or pounds are caused by lost motion in any of the revolving, reciprocating or vibrating parts of an engine, they may be detected and located by placing the finger upon the different parts while the engine is running very slowly or worked back and forth by hand.