SINGER 251 - Manual (Page 7)

ADJUSTMENT OF ROTATING HOOK OIL FLOW REGULATOR
Fig. 7. Oil Flow Regulator in Hook Shaft Bushing
The sewing hook is automatically lubricated. The
flow of oil is controlled by Oil Flow Regulator 140551,
Fig. 7.
Turn Regulator Thumb Screw counterclockwise to
decrease the flow, as indicated by the (~) sign under
its arrow on the head of the thumb screw.
The Oil Flow Regulator 140551 is set at the factory
for automatic lubrication of the hook under overage
sewing conditions.
Turn Regulator Thumb Screw (see 140551, Fig. 7)
clockwise to increase the flow of oil to the hook as
indicated by the (-|-) sign under its arrow on the head
of the thumb screw.
To determine whether the oil is properly flowing
to the hook, withdraw the bed slide and hold a
piece of thin paper under the hook while the machine
runs for ten seconds. There should be a pattern of three
oil sprays on the paper; two light lines on the outside
and one heavier spray in the center. If there is no
trace of oil or an excessive amount of oil on paper,
adjust the Oil Flow Regulator, as instructed above, or
replace the oil filter 143350, Fig. 7, in the head of the
hook shaft, as instructed on page 28.
HINTS FOR PERFECT OPERATION
If the sewing hook should become excessively warm,
it may be due to an insufficient supply of oil to the
hook (see instructions, above, for adjusting Oil Flow
Regulator).
Keep the oil level in the oil reservoir at the HIGH
mark.
Clean out any lint or other waste around the hook,
around the needle slot in the bobbin case holder
and between the feed rows on the under side of the
throat plate.
Clean out any lint or other foreign matter that may
have collected around oil return passages, particu­
larly at oil return hole in rear arm shaft bushing.
When in operation, the top of the machine pulley
must always turn over toward the operator.
Always keep the bed slides closed when the ma­
chine Is in operation.
Do not run the machine with the presser foot resting
on the feed without some fabric under the presser foot.
Do not run the machine when both bobbin case and
needle are threaded unless there is material under the
presser foot.
Do not try to aid the machine by pulling the fabric
lest you bend the needle. The machine feeds the work
without assistance.
NEVER TOUCH THE STITCH REGULATOR PLUNGER
WHILE THE MACHINE IS RUNNING.