1949 Cub 12volt wiring

[Cubminister]

Sorry club members, I posted to another forum... new to the club.

I restored my working 1949 Cub and put a new wiring harness from a vendor listed on the forum. I followed all the instructions for a 12 volt Cub with an alternator. After completion, I fired the Cub right up but could not turn it off when I pushed the on/off starter button, which is two-pronged. I am not an electrical guru, just mechanically inclined. Any help is GREATLY appreciated.

I am also restoring a 140, but that is another forum with questions.
Thanks!

P.S. I am sure you men might need more info to which I will provide, just knowing I am not good with electrical.

[Eugene]

Need to know which alternator you used? 3 wire? 1 wire? Manufacturer's name?

Which wiring diagram did you use?

Welcome.

[John *.?-!.* cub owner]

If you have a 10SI alternator this may help. Be sure to read the notes at the bottom. My diagram does not show it, but the warning light can be replaced by a diode. The light or the diode as the case may be allows the ignition switch to excite the alternator, but lowers the return voltage to the point it will not allow the exciter lead to power the ignition. the light can be replaced by a simple rectifier diode rated at 5 amps or more, with the band end toward the ignition switch.

[Gary Dotson]

John's posting, above should help you out. If your alternator is not a Delco, the same correction applies but the connection points are labeled differently. If you're unsure which alternator you have, post a pic. of it. John, the diode does not need to be that heavy, many folks use 2 amp, I've been using 4 amp.

[John *.?-!.* cub owner]

....... John, the diode does not need to be that heavy, many folks use 2 amp, I've been using 4 amp.

I could not find the diagram that listed that diode, and was going by memory, which is older and more worn than my cubs. I did not know what the current draw was on the exciter lead, so I decided to error on the side of higher current.

[Eugene]

Post back with the alternator name or a photo and which wiring diagram you used.

We are assuming that you used a Delco 10SI. BUT, you could have used an make of alternator, even an older model with an external regulator.

The diode or lamp are common methods of preventing the alternator feed back to the ignition system. There are other methods, just depends on your personal choice.

[Cubminister]

Need to know which alternator you used? 3 wire? 1 wire? Manufacturer's name?

Which wiring diagram did you use?

Welcome.

It is a Delco, single wire. I purchased the new wiring harness with instructions, no diagram, from Brillman. I just read on their website that they offer technical support but sounds like you men give simple, detailed advice.
Thanks.

[Glen]

Hi,
Below is a wiring diagram with info about the diode, at the bottom of the pic.

If it is a 1 wire alternator, I don't know why you are having problems shutting off the engine.

The diagram is for a 3 wire Delco alternator, they have said on here if you have a 1 wire Delco alt, don't connect anything to the 1 and 2 connections on the side of the alt.

In the diagram, they only use the diode on a 3 wire alternator, on connection number 1, on the side of the alt.

Look at the alt and see if the 2 connections on the side have a cover over them, or if the hole for the plug is open, and has 2 connections in it.

The pics of 1 wire Delco alternators have a cover over the side connection, it isn't used.
Below is a pic.

[Eugene]

I purchased the new wiring harness with instructions, no diagram, from Brillman.

What does the wiring harness instructions say about installing the harness on the alternator?

[Gary Dotson]

The diagram Glen posted is a good one to use, if you have a three wire alternator. Pay particular attention to the notes, shown. I have, at times, had issues with warning lights. If you go that route, be sure to use one of the lamp #'s mentioned in the notes. If you decide to use a diode, they can be sourced from any electronics store.

[Cubminister]

Hi,
Below is a wiring diagram with info about the diode, at the bottom of the pic.

If it is a 1 wire alternator, I don't know why you are having problems shutting off the engine.

The diagram is for a 3 wire Delco alternator, they have said on here if you have a 1 wire Delco alt, don't connect anything to the 1 and 2 connections on the side of the alt.

In the diagram, they only use the diode on a 3 wire alternator, on connection number 1, on the side of the alt.

Look at the alt and see if the 2 connections on the side have a cover over them, or if the hole for the plug is open, and has 2 connections in it.

The pics of 1 wire Delco alternators have a cover over the side connection, it isn't used.
Below is a pic.

Thanks... this diagram is better than the instructions (no diagram) from Brillman. Will try this after work today.
THANKS!

[Cubminister]

I purchased the new wiring harness with instructions, no diagram, from Brillman.

What does the wiring harness instructions say about installing the harness on the alternator?

With Brillman, each wire has a number and the instructions tell which ends connect to which switch/part/etc.

[Eugene]

OK. How many wires are attached directly to the alternator? Guessing 3 wires.

If 3 wires, remove all but the wire attached to the large terminal. Start engine, see if the alternator charges and the engine shuts off.

If alternator doesn't charge but the engine shuts off, you have a 3 wire alternator and need the diode.