3 015 021 AVERAGE FIXED POINT Af at MOVABLE POINT Fig 11 5 Checking Breaker Points Gap c Internal shorts in the condenser d Excessive arcing caused by an abundance of oil on breaker contacts This oil is liberated from the combustion blower motor e Defective movable arm f Worn cam g Blown combustion blower fuse The gap may also be checked after removing the cap fig 11 5 The gap should be 015 to 022 as the average of the settings on each lobe Gap on first lobe plus the gap on the second lobe divided by 2 should be equal to 015 to 021 If adjustment is required install a new breaker cam and recheck the gap The cams should be smooth and not scored or worn as this will result in improper gap If the gap is still out of tolerance a new ignition unit base assembly should be installed Set the gap by adjusting the threaded contact to the prescribed setting When the proper setting is attained lock the adjustable contact in place with solder Use resin core solder only The condenser solder joints should be inspected for loose connections which will result in weak and intermittent spark causing heater backfiring or popping F Ignition Coil The ignition coil is mounted outside the heater case Inspect the spark plug cable for damage which may result if it is pinched Also examine the cable to see if it is securely screwed into the suppressor inserted in the end of the coil and inspect wiring connectors on the coil If breaker points test was satisfactory and a coil test is desired proceed in the following manner 1 Disconnect the electrical connection to the fuel solenoid coil white wire single connector on heater case and position it so that it does not touch a ground point 2 Remove the spark plug cable from the ignition coil and insert a cable with a standard automotive plug gapped to 085 in it Provide a ground for the plug 3 Place the ignition switch in ON position and set temperature controls for maximum heat output If a hot steady spark is present the coil and breaker points are operating satisfactorily If the spark is weak or intermittent and the breaker points have previously been proved satisfactory the coil is probably defective G Spark Plug The spark plug located in the burner assembly has a single electrode with the ground electrode welded to the mixer cup It is extremely important that the ground electrode be positioned in the proper location and that the spark gap should be correct Otherwise carbon may accumulate on the electrodes The result will be failure to ignite no heat or backfiring or popping noises If a complaint of no heat is received and the source of trouble cannot be otherwise located it is possible that a carbon bridge has formed across the spark plug electrodes A carbon bridge may be caused by low fuel pressure to the heater an improperly positioned spark plug ground electrode incorrect spark plug gap improper spray pattern or slow combustion motor speed caused by fan switch overtravel A simple test may be made as follows 1 Break the connection from the overheat switch to the solenoid lead on the solenoid coil white wire to prevent fuel flow Be sure the terminal does not touch ground 2 Set Heat control in high heat position turn the ignition switch on and put the Fan control on low The combustion blower and the ventilating air blower should run In a relatively quiet area it should be possible to detect a slight buzzing sound under the instrument panel In a noisy area disconnect combustion hose from combustion blower hold hose to ear and listen for buzzing sound The sound is generated by the spark If no sound is heard it means that the spark is not jumping the spark plug gap perhaps because of a carbon bridge being formed across the gap The carbon bridge may often be easily removed by the following procedure Pull the center wire out of the heater coil and hold it 1 4 from the coil center terminal This will cause the spark voltage to increase to a higher value necessary for the spark to jump the gap between the wire and coil terminal This results in a stronger spark at