engine and drivetrain YIKES, my starter won't turn off!!!!! (long)

[jerry]

i am currently experiencing a starter motor that will not turn off. i had to frantically disconnect the (-) terminal on the battery to stop it. reconnecting the neg-terminal did not cause the starter to continue, fortunately. However, my next try with the ignition key caused the same continuous starter event.

BACKGROUND: i've been tinkering with a 12-fuse mid-71 02 for the past month trying to get it to run. i swapped in a freshly rebuilt (by me) Solex single-barrel carb (in fantastic, barely used condition i discovered). the car has the cleanest, most intact engine bay wiring harness i have ever seen on any 02. suspecting that the starter motor was a bit 'long-in-the-tooth', because it didn't turn the engine with authority, i swapped it out today with another starter i cleaned up and refreshed recently. i set the points, valves and positioned the distributer with No.1 cylinder at TDC. exchanged the fuel pump too.

Car started right up with the first turn of the key. Yey!!!!!!

I could not get the car to idle properly with the Choke closed after warmup. it would die on me.

it was after a couple tries with the ignition that the continuous starter problem arose...

i am wondering if perhaps i used too much grease in the starter armature bushing and an electrical contact is occuring?

when this event occurs, turning the ignition key to OFF and removing it does not kill the starter.

disconnecting the neg-terminal and reconnecting it does indeed turn the starter off.

the wiring in the cockpit looks good and original. hazards work, blinkers blink, fuel guage works, alternator light functions....

this particular starter is itself old, but i cleaned the commutator and gave it a general 'once-over' and tested it at Kragens. I did notice that there was an initial spark upon firing up in the test stand. i attributed that to loose metal filings or some such.

any ideas????

[jetdog]

my Alfa does this if the starter is cranked too much. I haven't dug into it but I suspect it is a bad starter solenoid. I'm sure others will chime in, but I believe the starter solenoid acts like a big relay.

[02for2]

Sounds like the starter you refreshed wasn't assembled properly, or was gresed too much, or not cleaned up enough.

Current from the battery is applied to the solenoid, through the ignition switch, and it pushes out the drive pinion on the starter driveshaft and meshes the pinion with the ring gear on the flywheel of the engine.

The solenoid also closes high-current contacts for the starter motor, which begins to turn. Once the engine starts, the ignition switch is released and, a return spring in the solenoid assembly pulls the pinion gear away from the ring gear on the flywheel, and disengages the high current contacts, causing the starter motor to stop.

You probably have a broken, gummed-up, or mis-set return spring which is not allowing the electrical contacts to disengage.

Cheers!

[jerry]

thanks guys for your responses. this makes sense.

this particular starter was removed from a car that sat for years. the solenoid was initially immobile. i squirted some PB Blaster in it and worked it free.

Are solenoids available separately? i know i can just buy a remanufactured starter, but there's no sport in that...

[jgerock]

One other area to inspect before the solenoid is replaced is your ignition switch. The switch itself could be bad, causing the solenoid to stay activated.

New solenoids should be available. This part is what typically goes bad more than the motor itself - especially if the starter is heavily used for many years.

Jot down the numbers on the solenoid and Google your way to a new one.