Oh, RATS ...
my Johnnie won't start!
My JD was starting just so great ... new batteries, compression release ... even in cold weather. One day I started it up & let it run to warm up. After about five minutes, it died ... and, I just didn't start it again that day.
But, that was the last time I could get it started! I tried many times ... Mike & Ben have tried.
My "shop manual" for the 730 arrived; I've printed off stacks of Internet info; Mike & Ben took the starter & generator in to get checked/fixed.
With the wiring diagrams now, hopefully the whole rotten, complicated electrical system can be upgraded. I've been advised to "keep it stock".
That 24 volt 730D of yours is both a positive & negative ground tractor.. That’s a little different than used on most other equipment..
On half of the batteries & one half of the electrical system uses 12 volts negative ground... The other half of the batteries & electrical system uses 12 volts positive ground & the starting & charging system use all the batteries in series for 24 volt starting & charging.. It seems complicated up front but once you understand it, it’s not that bad..
~That 730D essentially uses 3 separate electrical systems [all interrelated but isolated from each other].. That tractor used one 12 volt system to power ½ the lights, fuel gage & accessories, the other 12 volt system to power the other ½ of the lights, accessories & rear lights.. When the starter button was pushed all the batteries were used in series to power the starter & of course the generator needed to charge all the batteries in series at 24 [actually 27-28] volts..
~The 24 volt part of the system is COMPLETELY isolated from the tractor chassis with no part of the 24 volt side touching the metal tractor chassis [starter & generator are isolated from the chassis] .. The 12 volt sides do have return to chassis grounds [one positive & one negative]..
~Your 730D originally came with 4- 6 volt batteries wired in series with 2 batteries providing ½ the 12 volts & the other 2 providing the other 12 volts.. The left 2 batteries supplying the positive ground part & the R/H 2 batteries providing the negative ground part.. There was a small connector wire hooked between the center 2 battery’s connector battery cable & seat box ground..
Most people now just use 2 large 12 volt batteries in place of the original 4-6 volters.. The L/H battery [or batteries if 6 volters are used] hooks the most negative post to the starter’s solenoid post & positive post to the other battery [or batteries ].. The R/H battery [or batteries] hooks the most positive post to the stud on the side of the starter & the negative post to the other battery(s).. You also need a ground wire hooked from chassis [battery box] ground to the cable connecting the two center batteries together..
I know this would go quicker if my mechanics didn't have to work outside in sub-freezing weather...!
My mechanics are in real life the lumberjacks logging in my woods. See lots of photos from fall into winter on the logging projects. Logging (click here)
Helping to make the logging trails with the drag.
We've got the loader repaired & in use ... new hydraulics.