ENGINE DIAGNOSTIC TEST PROCEDURES Section 6 • MEASURE SMOKE INTENSITY (Continued) 10.  Determine  Bosch  smoke  number  and  compare  with Bosch     number     specified     in     Performance     Data Guidelines. 11.  If  smoke  emission  sample  exceeds  published  limit correct as required. NOTE:  Filter discs to be evaluated should show no signs of water drops or soot spots. Avoid excessive handling and particularly touching darkened surface as much as possible. Smoke Meter Maintenance 1. Soot   deposits   must   be   periodically   cleaned   from sampling  hose  and  probe,  depending  on  use  and smoke   densities   encountered.      Detach   sampling hose  from  pump  by  loosening   knurled   nut.      Blow compressed air through hose and probe. 2. Periodically inspect for leakage around filter clamping surfaces: a. Remove shield from probe and seal off end and side holes with a short piece of tight-fitting hose which is plugged on one end. b. Insert and clamp a filter disc in place. c. Cock   the   pump   and   release   in   the   normal manner. d. Time  plunger  movement  for  its  full  stroke.    A time   of   10   seconds   or   longer   indicates   filter clamping is satisfactory. 3. Periodic inspection of pump seal: a. Insert and clamp a rubber disc in filter holder. b. Cock and release   pump,   making   sure   to maintain pressure on rubber bulb. No perceptible movement of pump piston indicates satisfactory pump seal. 4. Periodic pump cleaning. a. Abnormal    force    required    to    operate    pump indicates need for cleaning. b. Disassemble,   clean,   lubricate   pump   cylinder, reassemble and check for leaks. CHART C* Representation of: BACHARACH OIL BURNER SMOKE SCALE DEVELOPED IN COOPERATION WITH SHELL DEVELOPMENT COMPANY This   scale   is   based   on   a   test   flue   gas volume  of  2250  cubic  Inches  per  square inch of filtering area, which is equivalent to 6  full  strokes  for  models  RZB  and  RAC Testers  and  10  full  strokes  for  Models RCC   and   RCC-B   Testers.    For    motor operated smoke meter see instructions for sampling period. This Scale Conforms to ASTM D 2156-63T SCALE No. Bahoroach Instrument Co. RR776 Pittsburgh Pa., U.S.A. Made in U.S.A. *Chart C compares darkness of filter paper to Robert Bosch Smoke Number. CG ES-240-4 Printed in United States of America Page 41