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MikeJW

Allis Chalmers 712H Just Purchased and Not Starting

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MikeJW

Good day everyone! Newbie tractor owner here trying to get my recent find off craigslist to start! 

It is an AC 712H. I paid $75 for the tractor, a nice heavy duty home built trailer with wooden sides, and an old plow which I think will fit this tractor. The seller told me he paid a mechanic to get it running 2 years ago, and it ran great then, but it's been sitting in the barn for 2 years and now will not start. The seller said he had charged the battery, but that it would still not start. When I got it home, I found that he had installed the battery with +/- terminals reversed, the red was on the ground. The battery voltage was also down to under 8V, so I swapped in a good battery from my Wheel Horse 314H (which is a low hours, mint condition tractor I also recently bought to be my daily user), and the AC 712H cranked, but still would not start. The cable connected to the starter actually got very hot and smoked, and when it cooled, it broke right off when I wiggled it a bit (photo attached). I don't know too much about troubleshooting engines, but I checked for spark using a screwdriver and did see any while cranking.

What is the next thing I should be looking for? Could the seller have burned something out by hooking the battery up reversed? Any advice on what to check would be greatly appreciated.  I've attached a few photos to this post so you can see what I am working with. Thanks!

 

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SimpleOrange

I'd like to see what is under the nut that secures the power lead to the starter, should be insulated and it looks like your getting a dead short.

Also possible the bendix gear is pre-engaged, this would prevent the starter from gaining momentum before engaging the gear. This condition usually happens when someone attempts to start an engine with an extremely low charged battery. 

The bendix is released by engine rpm once its running, if your able to turn the engine over manually this will also release a stuck bendix gear.

A low charged battery that is not able to supply full starting amperage is sure to burn out the starter in short order.

Now that your starter supply cable is burnt now would be a good time to replace it with a proper battery cable having the proper connectors. Most farm supply shops can make up cables to any length you need.

The farm supply near my home use a hydraulic crimper to secure the ends onto the cables.

Reverse polarity on the battery would possibly burn out the diodes on the bridge rectifier, you may have to replace the voltage regulator.

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Edited by SimpleOrange
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MikeES

Also do not crank these starters on garden tractors very long (I never go more than 15 sec continuous) as they heat up quickly.   Let them rest and cool awhile before cranking them again.

Pull the spark plug and crank the engine to see if you have spark, and the starter motor can crank much longer without compression and not get hot.

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deebig

That is simply a bad connection to starter. A poor connection will heat up and damage wire. As far as not firing up....run a wire from battery + to  the positive terminal on coil. This will bypass ignition switch and all safeties.

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MikeJW

Thanks to all for the responses! @SimpleOrange, attached is a photo of what is under the tape. 

@MikeES, I did pull the plug connector and it was not getting spark, but it was cranking pretty good and sounded like it had compression.

@deebig, I'll pick up a new wire and make sure it is a solid connection. Also, by safeties I assume you mean things like the cutoffs related to the PTO switch and Hydro Bar in neutral. Correct? I'll give that a try over the weekend.

If after all the above, it still does not get a spark and fire, what is the next thing to check?

Thanks again to everyone who responded! Looking forward to getting this machine running.

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Edited by MikeJW
Typo

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tadams

When you get the wiring fixed check the carb if it has set for 2 years this great gas they sell now will go bad. I would drain and clean the gas tank and fuel lines and drain the carb then add some fresh gas and add fuel additive, something like sta-bil or sea foam and try starting it then if it does not start leave it set over night. I have had good luck with this setting over night a soaking the gunk loose in the carb and then starting the next days.

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maxwood

Hello, I the past with these  machines, i have had problems with the starter switch  connector. disconnect the 5 prong plug that goes to the starter switch ,and clean those connections  also.

 

 

Thanks Ken in Mi

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MrSteele

Previous owner was, or worked around, an electrician! Clean all the contacts, clean the points with emery cloth and check the gap. Replace that starter cable!!. Just in case, put a rubber or nylon washer on the starter post before you put the cable on to act as an insulator. With a hot battery and the plug removed, try turning the engine over, and do as Mark suggested, check to see if you have spark across the points when they open. If not, check the wires to the points where they enter under the points cover. A bare wire there will drive you crazy. One of us knows this to be a fact. If grounded at the cover, you can isolate with electrical tape between the wires and the block before installing the cover. I am assuming the cover still has the gummy insulation that keeps the cover from wearing on the wires. Electrical tape will also work there, it is just not a permanent solution. You seem to have a connection/grounding issue

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fishnwiz

. If not, check the wires to the points where they enter under the points cover. A bare wire there will drive you crazy. .....

Have chased issues that ended up being exactly this...great advice. 

Edited by fishnwiz

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MikeJW

Rewired, cleaned the points, and checked the wire under the points cover. Not sure which did the trick, but got her running!

Thanks to everyone who posted. Took it for a quick spin around the yard just before it got dark. Tomorrow I'll give her a good cleaning and check all the fluids. 

One small issue I noticed is the throttle connection linkage. Seems to be missing a connector piece where it attaches to the lever on the carb that controls the throttle. I was able to rig it up so it works, but maybe someone can take a look at the attached photo and tell me what's missing? 

Thanks again!

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B10Dave

If you look at your picture you will see the clip at the bottom is on the wrong end of the link. Unclip it from the link; insert the round portion in the carb lever; put the link through it and reclip to the link. Hope that helps...Dave

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