# JD 400 w/ Kohler K532 electrical problems



## USAH (May 4, 2011)

hi-

i hope this is the section to post this question in. 

i have a late model JD 400 with a kohler K532 (iirc, i am 1000 miles away from tractor at the moment).

the tractor has been bullet proof reliable for many, many years. i am the second owner of the tractor, having bought it when it was nearly new. its got about 1000 hours on the clock, but i suspect the clock to be WAY off. realistically, i think its closer to 3000 hours. 

i am beyond anal about the maintenance. this year, when getting it ready to put into service, i discovered it had no spark. every now and then, it would fire, run for a few seconds then quit. 

i DO have a factory service manual for it. i started check the coil, wires, plugs, etc. i did discover one of the wires was fairly corroded. the resistance was way off when compared to what the book said. IIRC, factory was 18-20 ohms and one of the wires was reading 3.X ohms and the other 8.X ohms. 

i also checked the coil. i checked the coil using all points and methods as per the book. i am sorry, its been a few weeks since i did this and i dont recall the exact numbers i got or what the book said it should be. i do know, i was NO WHERE near factory. 

SO, i figured it must have been the coil. i started looking for a replacement coil and about fell over when i saw the cost (best price is about $140). so, i decided to go back and check ALL connections, clean and dielectric grease EVERYTHING. all looked good except the voltage regulator gang plug. it was totally melted to an engine shroud. i cut the gang off and replaced the ends. still no luck, it would not start.

that got me wondering if the coil is not really the problem. unfortunately i ran out of time to check the voltage regulator before taking off on a biz trip. 

so, i am writing to ask you folks if anyone has any BTDT experience with this. i need to get this machine running ASAP and really dont want to just start throwing parts at it. given that the center and right pin (as viewed from the front of the tractor) were shorting to the shroud, i wonder if its possible i blew the voltage regulator too. 

the major problem i am facing is i wont be back to the tractor for 2 more weeks and would really like to have the parts waiting for me when i get back. SO, should i go ahead and replace the coil even tho it may NOT be the problem being that it is way out of spec? what is the probability that i need to replace the regulator? if i should, can i get away with a cheap chinese one? i typically am adversed to doing that, but seeings that they are about 80$ for an OEM unit and $25 for a chinese one, the cost is very appealing to me. 

fyi, plugs are new. the points are fairly new (3 years maybe) and dwell is okay. 

thank you for any advise given.


----------



## USAH (May 4, 2011)

i solved the problem. i figured i would post the solution for all of u should this happen to you. i will give u the answer first then tell u what i checked. 

it was the micro switch on the PTO. i would add that i believe there were additional issues too, but the primary issue that lead to the no start was the micro switch. 

1) cleaned and dielectric greased the grounds.
2) noticed burn marks on the ignition switch wiring. replaced burned leads AND the switch. dielectric greased everything.
3) cleaned and dielectric greased all relay and breaker positions.
4) cleaned and checked continuity for, neutral safety switch, seat switch and PTO micro switch. dielectric greased everything.
5) replaced plug wires after finding them out of ohm spec.
6) installed new coil after find it out of ohm spec too.
7) noticed burn marks on voltage regulator so i replaced that too. 

of course the last thing i checked was the PTO micro switch. after by passing that, i started right up. runs fantastic. i will order a new microswitch when i get back in country and get it back to original configuration.


----------



## Tonyquinn (Feb 21, 2017)

kohler k532 misfires under load ,new points set,but cannot find any timing marks ,engine has simultaneous spark coil, seems to miss and backfire when just moving forward or any load on engine,runs on one cylinder for a bit then clicks in ,but no grunt at all,seems fuel related but,could be out of time ,but starts well,thanks Tony


----------

