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730 diesel question

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John

06-14-2003 05:30:48




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Can any one tell me how many volts you should have at the distributor of a 730 diesel pony motor?




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Clooney

06-14-2003 06:26:02




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 Re: 730 diesel question in reply to John, 06-14-2003 05:30:48  
John, not sure it's furnished anywhere. It also makes a difference on coil load & available battery voltage. ~With both points open & no coil load you should have full battery voltage...With both points closed & full coil load you will have probably be under 5 volts...with it running you will have more voltage as the dwell time is shortened...With the Diesel running & the tractor generator charging the voltage will be higher & around 7 with both points open & maybe 5.5+ with the pony running. ~During pony cranking the pony coil resistor is by-passed so you will have full battery voltage to the pony distributor [that will be lower than static battery voltage as the starter cranking load will lower the available battery voltage].
~I know this isn't much of an answer but without actually measuring the pony distributor voltage under ALL conditions & charting it there is no one voltage to give you.
~Bottom line, you probably need at least 4.5 volts while the pony is cranking, & over 4.5 volts with it running to operate properly. If it runs at over about 6 volts with the diesel generator charging you risk coil damage.
~What is the problem you are trying to solve? [email protected]

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John

06-17-2003 05:32:56




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 Re: Re: 730 diesel question in reply to Clooney , 06-14-2003 06:26:02  
Clooney thanks for your reply. I understood what you were saying. This is a long story. I have not used this tractor much for about 10 years because I could not get the pony eng. to run. Sometimes it would start if the weather was warm and everything was just right. When I had help we would pull start it, but most of the time I am alone. I thought the coils were bad but replacing them didn't help. Last fall the starter failed. After getting it repaired this spring I though I would try again. I had no ignition and used a jumper wire to jump the distributer and the starter and it ran perfect. I was checking voltage at the switch and this brought me to the question. I have ordered a new switch. Don't know if that will fix then problem.
John

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Clooney

06-17-2003 06:46:44




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 Re: Re: Re: 730 diesel question in reply to John, 06-17-2003 05:32:56  
John, a new switch is a good place to start, it also needs a pony coil resistor that goes on the back of that ign/light switch [you will have to ask Deere, I'm not sure that coil resistor comes on or with the new switch]. That resistor is what lowers the run voltage after the starter quits cranking.
~The 720D pony starter button is wired kind of funny as it isn't directly powered from the ammeter. Let me know if you need a wire pin-out of that push button switch to ign switch interface as I just drew one on the 720D for a guy a couple of days ago. Send me your E-Mail address [also state what you are working on as I get over 50 E-Mails a day & have a hard time keeping them straight, or for that matter even keeping up]�..
~If your new coils draw a little more current than the originals there MIGHT a problem with the original resistor supplying enough current to the pony coils while spinning up & cranking the diesel� F-I-T is doing some work on a problem in that area & as soon as he gets it figured out I�m sure he will be able to add new information to this area�

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