If the mouthpiece burner does not give a long, blue flame after cleaning, procure a new mouthpiece burner and replace the old one.
A yellow flame indicates too little air in the mixture. This can be caused from too large a hole in the gas tip, air inlet partly closed, dirty burners, or gas burning in the mixer. Sometimes the hole in the tip of the gas cock is too large. The hole can be paned with a small hammer and reamed out with a small broach to the proper size.
The pot burner top plate is fastened by four stove bolts. These bolts become charred and brittle from the heat, and the nuts will be very hard to start. Have a few of these bolts on hand when changing the plates, because the plate must fit tightly to the burner to obtain the best results.
Good slugs can not be produced with dirty burners. Keep them clean. It is better to spend ten or fifteen minutes cleaning the burners than to lose an hour trying to regulate the temperature of the metal.
To Remove the Gas Burners
Disconnect the hose on the older styles or the gas pipe union on the newer styles. Separate the mouthpiece burner from the crucible at the sleeve. (This operation is not necessary on the thermostat connections.) Pull out the rod which holds the burners in place and lift them out.
To remove the mouthpiece burner, take out the screw which holds the support to the jacket of the pot, slip the connecting sleeve back, and pull the burner to the left.
PRESSURE GOVERNOR
The pressure governor is used to control the flow of gas to the machine and to keep it at an even pressure. The governor is placed on the main gas line so the gas must pass through it before flowing to the machine. It is not necessary to have a pressure governor on each machine, for where there is more than one machine, a governor large enough to supply any amount may be secured.
The gas enters through a valve in the bottom of the governor and passes up into the supply chamber. From the supply chamber the gas flows out to the machine burner. The pressure in the supply chamber is regulated by an inverted cup float. The lower rim of the float is immersed in mercury, which causes the cup to float and also acts as a seal to prevent the gas escaping through the top of the governor. Weights are placed on top of the float to counterbalance the gas pressure. Fastened to the float is a rod which passes through the gas chamber. This rod connects to and operates the valve in the inlet opening. When the gas pressure is increased it raises the float by its pressure. When the float raises, it at the same time raises the valve in the intake, which decreases the opening through which the gas enters. Should the pressure in the main fall off, the float sinks deeper into the mercury, and the opening in the valve is opened, permitting a greater flow of gas. Thus the pressure in the gas chamber is held uniform, because the greater the pressure on the float, the smaller the opening for the gas to enter.