@ big End Bob....I'd suggest that your glowing starter was caused by the overspeeding (pinion engaged,with engine running wether starter is powered or not )
A starter needs an awful lot of power fed through it, over a fair time in order to melt the solder on the segments of the armature that are in contact with the brushes......A jammed starter will consume "lock-draw" current on a petrol-engine up to about 3 litres, that's around 250 amps Similar size diesel, 300-500 amps.
The construction of the starter is such that you would not get sufficient current to make it glow unless there was a serious short, battery virtually directly to carcase ("earth")
Usual scenario, starter is overspeeded, flings windings which wreck the brushgear (there's your short-circuit to earth! ) also the flailing tails will shred the field-winding insulation (another short! )
A battery will usually be discharged before the starter is sufficiently abused to seriously overheat.
A warning light will only tell you if the starter is energised , starter would sense from the main solenoid to motor-lead (on a P/E starter, that's the short, stout link between starter body and one of the big terminals on the solenoid endcap.
The light will
nottell you if the pinion is stuck in and the engine is destroying a non-energised starter.
In case of sticking of ANY description
SWITCH OFF MAGS...then master battery switch.
An overspeed can destroy a starter in seconds...a "dead" engine will crank for a couple of minutes without serious detriment to a good starter....that's why I suggest kill engine first.
A jammed pinion, which locks both the starter and the engine solid, can often be freed by turning the engine backwards...less than 1/4 revolution should free it.
an extreme jam needs the starter mounting-bolts slackened, normally the pinion will self-retract, otherwise a backwards turn will do the trick.
@ Mike Cross.... Absolutely correct! a swift "clonk" on the side of the solenoid (near the plastic endcap ) can, indeed free a lightly-welded contact. this should be followed by a new endcap and contact set fairly promptly
It does NOT necessarily mean the starter needs a full overhaul or an expensive exchange.
A "dead " starter will sometimes respond to a clout on the end of the starter body....if that works, it indicates sticking or badly-worn brushes the smack jogs them into making contact with the commutator.
A pre-engaged starter solenoid finds it's earth through the starter itself so a brush problem will mean it won't even click when energised.
If solenoid clicks, but starter doesn't rotate, suspect the main contacts...see above , re endcap. they do burn away, as they carry all the current and the solenoid smacks them together quite viciously!
Think I've thrashed this donkey to death!
here endeth "all you never really wanted to know about starters"
