69 2000 Starter/ignition wiring run-on

[eastmedia]

Hi All,
I have a late 69 2L I am starting on. It has the 4 pin plug for the starter harness, but no harness, just 2 wires connected to the plug after the firewall.
I was able to hookup the 2 wires to the starter. One to the positive/battery terminal, the other to the spade terminal on the solenoid.
Starter engages and car turns over, but the starter continues to run when the key is turned off.

I checked the wiring diagrams, but can't figure out how the starter is supposed to disengage after the key is released from the start position.

Is this wiring, or is it a fault ignition switch?

Thanks,
Ron

[JT68]

The wiring, a bad starter solenoid, or a bad ignition switch.

The solenoid on the starter needs to connect to the "start" wire from the switch-typically black and yellow.

The black and yellow wire should ONLY have 12V with the key in the "start" position. If it has 12V in "on" position you have a wiring problem or a bad switch.

If the black and yellow wire is only at 12V in "start" that is normal and the starter is at fault.

[garth]

JT's diagnosis is 100% correct on the possible failure modes. What ever the actual root cause is, you should also consider installing a starter relay right at the solenoid thus reducing the ignition switch starting current to < 1.0 Amp. The solenoid can draw between 40-60 Amps during engine cranking and represents a temporary overload for circuit's connections, conductors and the ignition switch contacts and eventually causing one the most common problems for roadsters. A Bosch type relay's contacts can handle 40 Amps continuously while its coil current is < 1.0 amp. A Bosch type relay cost $7 while a replacement ignition switch may cost $100. Inexpensive and a big improvement in reliability.

[unklpat]

40-60 amps during cranking is getting close to what the starter will draw, not what a healthy solenoid should draw. Correct me if I am wrong, but the solenoid only has to engage the starter, not power it,no? If the draw had the potential to be that much, I'd like to believe that the engineers designing our cars would have forseen the problem, and not been happy with a 10 guage wire run thru a 30 amp guage.
It's easy to check your switch, after removing the 3 small bolts holding it into it's housing. column most likely will need to be lowered for access. I've had good luck using "corrosionx", but CRC QD electrical cleaner would work. Saturate your disconnected switch, and work it back and forth until crud is washed out. Pat

[eastmedia]

The Start wire is only 12V at start position. I happened to be at an auto electric ship today and mentioned the problem.
He was familiar with the 2L and said the design of the flywheel gear is such that once the engine engages the momentum above the starter rotation helps push the starter gear back to disengaged?
I failed to mention the engine was without sparkplugs and compression, carbs, so "freewheeling."
Is that a possibility? Might it disengage with a bit more resistance?
Or since I verified the wire only has 12V at start position, the solenoid is just staying energized after power has been stopped at the key?