Electric Starter Effect on Glow Plug
Norvel engines usually start easily. On-going difficulty with engine starting is
sometimes a sign of a field-equipment problem.
Many fliers have a field box with a small 5 Ah motorcycle battery connected to a
power panel which powers the glow plug and electric starter motor. Common
high-torque electric starters designed to start .40 and .60 sized engines are too slow
to start small engines and sometimes draw too much current from the field box
battery.
Even though a glow plug may appear to glow orange (hot) when connected to the
field box battery by itself, it may cool substantially when an electric starter is
operated. This means that the glow plug will stop working just as the starter motor
begins to spin the engine, so the engine may not start. The plug will heat up again
when the starter motor is turned off, making it appear as though the plug is working
properly.
To check for this problem, plug a glow plug clip and a standard electric starter into a
power panel. Connect the glow plug clip to a glow plug, and cup your hands around
the plug to keep it out of direct sunlight. The coil should glow bright orange. Be
careful, the plug will get hot quickly.
Turn on the electric starter. If the field box battery is small, old, or low on charge, the
plug coil will cool and stop glowing. Turn off the starter and the plug will again glow
orange. Also, try operating the starter in one second pulses. Notice that the glow plug
remains hot longer if the starter is pulsed.
Op er a tor's Guide
Glow-Fuel Engines
4-12
LITE MA CHINES
