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SELF-PRIMING HEAD OIL SIPHON
Class 63900 machines are equipped with a self-priming head oil siphon. When the machine is started, oil
splashes on the priming cup felt, filters through the felt and trickles down the vertical oil tube, thus priming
the siphon. Once the prime is established, it is maintained, unless the felt is removed. The siphon operates
twenty-four hours a day, removing oil at the rate of six to twelve drops per minute, which, of course, far
exceeds the rate at which oil collects in the head.
INSTALLING AND MAINTENANCE OF OIL SIPHON
A newly installed siphon starts its action within three to five minutes after the machine is operating. However,
it may be twenty minutes or so before all the air is removed from the line and the siphon is in full operation.
Within an hour, there should be a distinct reduction of the oil in the head sump. If the siphon does not
function, determine if the siphon intake tube, located in the head, is inserted in the felt block and that the
plastic tube is connected at both ends. If the above two items do not correct the siphon, replace the siphon
felts as described below.
The felt in the priming cup is designed for a specific purpose. This felt, No. 666-237, is to meter the flow of
priming oil and to prevent the entrance of air. The felt also acts as a filter and keeps the siphon clear of lint.
If the priming cup felt and the intake felt (666-214) becomes contaminated with an excessive amount of lint,
it may be necessary to replace the felts. The priming cup felt is replaced by removing access plug at back
of machine and replacing felt 666-237. For the best initial self-priming condition, the felt of the siphon should
be installed dry. The intake felt is replaced by removing the end cover.
However, if for some reason the priming cup felt has been oiled before installing, the siphon may fail
because air is trapped in the felt. As a precaution, remove felt from cup. Then, while squeezing the felt
between the fingers, saturate it well with oil. In other words, squeeze out the air and replace it with oil. This
prevents the trapping of air, and no trouble should be experienced when starting the siphon.