Converting 720D pony start to electric start

chas036 · Sep 7, 2016

I have major clutch problem with the pony motor in my 720, and I am tired of dealing with this pony motor, so I want to remove it and install an electric starter. I already have all the hardware like mounting bracket, ventilation tube, cover plates, 12 volt generator, and block water line plug that I got from a scraped 720D electric start tractor years a ago. I saw a conversion kit from AbilenMachine that uses a 12 volt motor instead of the 24 volt motor, which you can see below.

http://www.abilenemachine.com/john-deere-tractors-pony-motor-to-12-volt-conversion-kit-12V720-K.html

My question is, has anyone used this motor before, and does it turn over the diesel a speed good enough to start it? Will a regular car 12 volt battery work, or do you need a special 12 volt battety? I will not be using the tractor in the winter, so cold is not a problem.

tomstractorsandtoys · Sep 7, 2016

I have not used one but can tell you that I have changed a dozen 3020-4020 tractors from 24 volt to 12 volt with no problems in how they spin over. You are going to want the highest amp battery that will fit in your battery box. The electric start tractors used a larger battery box so getting one of those will give you room for a larger battery if needed. Tom

johndeeregreg · Sep 7, 2016

mine was 12 volt electric start when i got it. not sure if same starter as the one your looking at though. mine has a 1000 cca battery, like they use in the 8000 JD tractors, and it wouldn't turn it under compression much below 45 degrees with out the booster on it. probably would have been better with 2 1000 cca battery's but i never tried it, i found a pony converted to 12 volts and dropped that in, now it will start below 0 degrees. it was much quicker to start with electric start when the battery had it in it to turn it over, not having to start pony let it warm up and go through the whole cycle.

chas036 · Sep 7, 2016

I contacted that Abilene Machine and they only sell the whole kit and not the starter alone. Does anyone know what type of 12 volt electric starter would bolt into the 24 volt mounting bracket on a 720 ?

johndeeregreg · Sep 7, 2016

call Ag Electrical Specialists out of Racine MN they put together kits and im sure they will sell just the starter. their number is 507-378-2101. they should be able to answer any questions you have about converting it as well

buickanddeere · Sep 7, 2016

Drops the value of the tractors being a cross breed.
The starting engine is 14HP and in cold weather it's all used to turn the diesel under compression . I see a lot of slam starts where the diesel is rolled over without compression up to speed then compression is added. They either start on the first compression stroke or the whole process is started over again. Lots of cylinder wall wash down with raw fuel.
A single group 31 battery with 1000CCA will at most power 8HP worth of starter.
Even with just 376 cu" of displacement on a two cylinder. It's more difficult to crank over than a six cylinder of the same displacement .
A Denso 5KW starter is 6.7HP. Delco 42MT on 12V is up to 7.3KW or 9.75HP. 50MT on 12V is 8.5KW or 11.3HP drawing 2000amps. The new PM 44MT has the same power as a 50MT with a little less current draw.
Considering the cost of the starter , cables , updating to a larger 24V battery box and a pair of group 31 batteries every 3-5 years . I don't see saving anything over a starting engine .

chas036 · Sep 7, 2016

Just to let everyone know who is looking at this thread, I called Ag Electrical Specialists and they will make up a 12 volt starter for #315. Since I have all the mounting brackets , I think I will be taking off my pony and replacing it with a electric starter.

If anyone is interested in buying a good running pony motor, along with a new 6 volt battery, and a new one wire 6 volt positive ground alternator all for $600, leave a note here. I live in upstate NY. The pony clutch has some problems engaging and probably needs overhaul, but the motor starts everytime and runs good. It also has a new water pump last year.

OldCrow51 · Sep 7, 2016

(quoted from post at 18:02:44 09/07/16) Just to let everyone know who is looking at this thread, I called Ag Electrical Specialists and they will make up a 12 volt starter for #315. Since I have all the mounting brackets , I think I will be taking off my pony and replacing it with a electric starter.

If anyone is interested in buying a good running pony motor, along with a new 6 volt battery, and a new one wire 6 volt positive ground alternator all for $600, leave a note here. I live in upstate NY. The pony clutch has some problems engaging and probably needs overhaul, but the motor starts everytime and runs good. It also has a new water pump last year.

I'm sure many would jump on a good running pony motor but why not keep it so you can add it back to original configuration in the future? As someone else posted it will be worth more in that configuration.

Blksmok · Sep 7, 2016

IMHO it's easier to fix the pony engine problems than to convert to e/s. I have purchased several 70 diesels that were kind of converted to e/s w/o having all the right parts. The 12 e/s I had would crank the diesel on decompression mode but stall the starter out on full compression. Even the 24 volt systems need good batteries and fast cranking speed to start the diesel. It started the diesel good until the temperature dropped to 30 degrees and then the cranking speed and cranking time were reduced. A tank heater would correct that problem though. As others have said..the resale value of the tractor is generally reduced if it's not original, complete and done correctly. Accidental arcing on 24 volt systems scares me. It will melt a battery post in just a few seconds.

ejb17 · Sep 7, 2016

Where in upsate? I am near Buffalo. Would be interested in the pony.

fdt860 · Sep 7, 2016

Unless you have a loader on it and you use it everyday for all kinds of chores, this is not worth it.

Converting 720D pony start to electric start

chas036

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tomstractorsandtoys

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johndeeregreg

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chas036

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johndeeregreg

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buickanddeere

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chas036

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OldCrow51

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Blksmok

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ejb17

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fdt860

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