Jacobs Ignition Run-on Fix (from an email question)
These are responses by John Locke & Jim Blair to a Jacobs ignition question emailed to me.
As far as the problem of running after you turn off the key, you can call Jacobs and tell them you need a diode for the alternator wire and they should be able to provide you one or you can go to radio shack and buy one rated at 12 volts or more and at least one amp. Install it in the wire that energizes the alternator with the marked end towards the alternator(if that does not solve the runon problem turn the diode around.). I think that is the brown wire. I have one on my CJ 7 with the stock 6 cylinder. I also had one in my J-10 with a Chevy 350 that had the run on problem without a computer. I took it out because I wanted to keep things as simple as possible. I only used the Jacobs for one day in my truck. I really like the one in my CJ but the one I bought for the truck is sitting in the box now. If you have trouble getting this to work out right email me back. John Locke