Got No Juice!

[tbbahner 27]

Hi all,

Rebuilding an old C160 8spd. Wasn't charging but would start and run, don't know how but it did.

Anyway, I decided to ditch the old cobbled up wiring, bypassed all the saftey switches, and wired it point to point according to the wiring diagram. Even put in a new rectifier.

Turned the switch on and saw the ammeter twitch. Hit the starter and it started running, ammeter was discharging instead of charging. Figured I had the two ammeter wires crossed, so shut it off since it was running on gas in the carb bowl -

I'd removed the gast tank for easier access to the switch.

Switched the ammeter wires, put in gas tank, started it up to test run, Every thing looked great. As I was idling out of the shop, it died. Dead, like I lost ground or positive. No juice at the coil, no juice anywhere using the switch. Battery cable grounded to the starter bolt on engine, so ground is good.

Turned engine over by jumping solenoid posts, spins it over just fine so its not battery. Wired up a known good switch from a C141, pins are different but since wires are individual, should be right. Same thing. Checked continuity of all new wires and they're all ok.

I lost something somewhere, but can't locate it. Any ideas??? No fuses, nothing on the accessory pin.

This things driving me nuts. Has to be something simple but I'm not seeing it.

Any suggestions appreciated.

Tom B

[rmaynard 14,861]

First, make sure that you have a good ground from the battery to the engine/frame.

Disregard all the wiring but the coil. The engine should run without the charging circuit hooked up. Just hook the coil directly to the battery to test it.

Make sure the coil is grounded, and that the (-) terminal is connected to the points and the condenser. Then take a wire and go directly from the (+) side of the battery to the (+) side of the coil.

Activate the starter and the engine should run.

Once you know that the engine will run, disconnect the wire from the coil, and using a multi-meter or test light, work backwards until you find where you are losing the (+) 12 volts between the ignition switch and the coil, or from the ignition switch to the (+) side of the battery. I would suspect it's the ammeter.

If you don't have a wiring diagram, here is a copy.

Edit: You didn't mention what year the C-160 was. You may have a seat switch in the coil circuit.

[Kelly 1,028]

Do you have power to the switch? if yes do you have power to the + side of the coil with the key on? if no you may have a bad switch, try what Bob said also.

[tbbahner 27]

Thanks Bob and Kelly.

I've never had an ammeter go bad but that would seem logical since it appears like I lost the 12v positive side, and thats the direct route to the switch.

Its a '76, all the interlock switch wiring has been removed.

This thing started and ran 3 times without a hitch.

I'll go out and do some more checking. Thanks for the hints.

Tom B

[tbbahner 27]

OK, how hard can this be - 4 frickin wires. Anyway, I'm back to where I was yesterday. Installed ammeter from another tractor. Here's a pic of the switch wired up.

I have power to the switch and coil now. Here's a pic of the gauge with the key off.

But when I switch the key on, the guage moves to the + side. It should move to the - side shouldn't it.

The wire from the battery side of solenoid goes to the + side of the ammeter and the wire off the B post on the switch to the - side, ?Right?. The diagram a little unclear on this.

I don't want to switch wires around and burn up another gauge if I can prevent it.

Have I got somethng wrong yet?? Or, should I just fire it up and see what smokes?

Thanks for any tips on what to look for.

Tom B

[rmaynard 14,861]

Correct. The + side of ammeter goes via red wire to the + battery side of solenoid. The - green wire goes to the B terminal of the switch. When you turn the switch to the run position, you should then have 12 volts at the "I "terminal. From there, the circuit continues through the PTO safety switch and clutch safety switch to the coil. Since you said that you bypassed those switches, unless you have a break in the wire or a bad terminal end, there should be 12 volts at the coil.

Edit: My 1976 B-100 has a safety switch under the seat that ran through the PTO switch. It acts like a kill switch by removing power to the coil. Did you bypass that as well?

[tbbahner 27]

Yep, all saftey switches are gone from the wiring harness.

When I turn the key to run, I have power to the coil, it will kick the starter if I turn the key to start and I'm pretty sure the engine will start again no problem.

What is confusing me is what I'm seeing on the ammeter. same thing as last night before I tried to idle it out of the shop and it died - burnt the ammeter up. Needle goes to the plus side when I turn the key on. If I started it up, ammeter would show discharge, almost like the old generator/reg. that didn't get polarized.

Don't really want to switch the wires so the gauge reads right, figured it would burn another good ammeter up.

This thing is going to drive me to drink,,,MORE

[rmaynard 14,861]

Sounds to me like you have the ammeter wired backwards.

[tbbahner 27]

Thanks for you help.

Was being overly catious I guess after the ammeter shot craps. Swapped the wires, fired it up and mowed with it for a half hour. Bad ammeter is a 1st for me, will definitely remember this experiance.

Now, on to other issues.

Thanks again Bob and Kelly.

Tom B

[Save Old Iron 1,563]

Tom,

for purposes of troubleshooting, the ammeter is electrically the same as a very small resistor (more like the equivalent of a 2 inch piece of 12 gauge wire)

You cannot harm it by reversing it - the indicator will just end up pointing in the wrong direction.

To eliminate the ammeter as fault, just put a jumper wire directly across the two wires coming into the back of the meter.

[tbbahner 27]

SOI, thanks for the info. I wondered if I could do that, but didn't want to burn anything else up. Guess I error on the side of caution, too much some times.

With a wiring diagram and an old analog meter I can usually figure things out, even though I don't know the full function of all the pieces.

Thanks again.

Tom B

[Save Old Iron 1,563]

Tom,

check out this post

http://www.wheelhorseforum.com/index.php?showtopic=24214

it will give you some idea n the ultimate simplicity of the construction of an ammeter gauge.

[bowtieguy 334]

It must be HOT in KS...I've heard lots of excuses to break open a BUD Lite....but I don't think I've heard of using an ole ammeter....Good work Tom.

Funny, but I just rewired an ole Raider 12 today and the ammeter "reads backwards"....hummmmm....