129 starter runs constantly
 

I have a 129 which I inherited and I have been reworking to get it running. I replaced the key switch and now when i turn the key to run the starter/generator runs constantly . I have not changed any wiring except bypassing the neutral switch as the tab to it is broken. I have fresh new battery and a new aftermarket voltage regulator. Any help on this would be appreciated.

First, welcome to OCC.......... :Welcome2:

Sounds like your have the wrong V/R and/or it is wired wrong.

Or the wrong key switch.

So, when did the constant run start happening?
When you replaced the ignition switch OR when you replaced the voltage regulator? either one can cause the problem as so very well stated by Iron Man and Roland.
Lets start with the easy one. the regulator.
Is it really the correct one?
Do go by the LABELED terminal ends on the regulator, not their physical location!!!
as there is no standard to them, they can put them where they please.
if no joy there, then on to the ig sw.
There are many so called "will fit" switches that are different as far as what is connected in what position they are turned too, and cause just your problem.
Hope this helps you when following the wiring diagram to find the problem.
if you kept the old switch/reg you can substitute back to them to see where the problem is.
Always change one thing at a time if you didn't, it helps if something is not right.
lets us know what you find.:bigthink:

Welcome!

I'm not familiar with the 129 wiring but I suspect there is a solenoid in the starter circuit?

There is no starter sol, it is old skool, a starter/generator.:BlahBlah:

According to the wiring diagram, there is a starter solenoid! New skool stuff!

I don't have a 129, but I know that my 123 and 125 both have a starting solenoid.

yep ,under the dash on the right side !:beerchug:

It's got a solenoid, but it's kind of hard to understand your scenario. The s/g runs all the time when there's a battery connected? Only after you've started cranking it?

Try again with some background on when/how this started happening.