Craftsman 161.210400 Owner's Manual

, use _TestNumberi6--initia] ignition TimingThis test should be made following any dwell adjustments as the pointsetting controls the basic ignition timing. On electronic ignitionsystems refer to the vehicle service manual for special instruction_. Sparktiming controls are used to advance or retard timing. Follow manufacturer'sservice procedures to check & adjust timing properly.I. Connect a timing light to the battery and #i spark plug cable as_illustratedbelow, in Fiqure 38.2. Rotate the Function Selector Switch to the RPM position and set the RPMrange selector to the Lo-1200 RPM position for idle speeds and the Hi-6000RPM for the high speed tests.3. Locate the timing mark on the fly wheel and degree indicator plate.Clean both surfaces and apply a white chalkmark on the fly wheel markfor good vlsibility.(Figure 35)4. Consult your vehicie service manual or tune-up decal under the hoodto determine which, if any vacuum hoses must be removed for propertiming adjustment. Make sure to follow all timing instructionspertaining to your vehicle. The above illustration shows the vacuumadvance hose disconnected and plugged.(Figure 37)5. Close starter shunt, start the engine and operate at specified enginespeed. Refer to vehicle tune up specifications label under the hoodfor proper RPM.6. Operate timing light and aim it at the timing mark. Note the position of thefly wheel mark in relation to the degree indicator. Compare to specifiedinitial timing. If not within specifications, readjust distributor asrequired,7. TIMING ADJUSTMENT. To change timing, loosen the d_stributor hold downscrew or bolt and rotate the distributor body as shown in Figures36 and 37. until proper timing is indicated.Test Number 17--TimingAdyanceSystemsNOTE: The following centrifugal and vacuum advance tests are generalones and may not apply to many of.the more modern vehicles. Many of today'svehicles have complex emission and ignition control systems which may alteror prevent spark advance from taking place under various conditions. Itis therefore very important to consult your vehicle service manual forthe proper procedures to check and/or repair advance systems.Ao MechanicalCENTRIFUGAL ADVANCE. With the distributor vacuum hose disconnected andplugged, operate the engine at specified idle speed and note positionof timing mark. INCREASE engine RPM slowly and observe movement of timingmark. The mark should move steadily and without jerking in the oppositedirection tO fly wheel rotation, up to approximately 1800 RPM. Decreasespeed and mark should return smoothly to its original position.VACUUM ADVANCE TEST. Operate the engine at 1500 RPM and connect the vacuumadvance hose to the distributor vacuum control and observe movement ofthe timing mark. The mark should move opposite to fly wheel rotationand may appear beyond the range of the degree indicator with a normaloperating vacuum control.