Green Tractor Talk banner

1 - 10 of 10 Posts

·
Registered
Joined
·
4 Posts
Discussion Starter #1
OK, new to group and need some help. I have a John Deere 318, best I can tell it's about 30 years old. I've had it for 15 years and absolutely love it. I really want to fix it as I'm hooked on it for sure.

*tractor will just cut off and I can hear the 25amp circuit breaker clicking on and off. Sometimes it keep clicking on and off until I disconnect the + terminal from the battery or it cools down.
*before it got to this point, the battery and PTO lights will come on and off, but not cut the tractor off. If I stopped to empty the bags, it was a struggle at times to get the PTO running again.
*when the tractor cuts off (circuit breaker trips), there are no dash lights on at all.
*Usually does it on hot days.
*Battery is new
*turning the ignition switch off doesn't help, you can still hear the breaker cycling on and off
*Mine positive battery lead has a small wire branching off of it. This wire gets really hot. The best I can tell, this wire goes to the 25amp circuit breaker and then on to the voltage regulator.

I suspect it's the voltage regulator, but want to troubleshoot for sure. How can I pinpoint this bizarre behavior? I don't want to just start replacing parts.
 

·
Premium Member
Joined
·
3,966 Posts
Sounds like you have a short some where after the circuit breaker and before the ignition switch. I sure someone will beat me to it but if they don't I will post the electrical diagrams. If you can post the S/N for your tractor as there has been several revisions over the years.


Sent from my iPhone using Tapatalk
 

·
Super Moderator
Joined
·
2,741 Posts
Your tractor is a 1986 model.

I moved this to the Hydrostatic Drive section underneath the Vintage L&G forums. You will find a few threads on similar 318 issues in this section.
 

·
Registered
Joined
·
1,668 Posts
Here are a few things to try and why I suggest them.

1. disconnect the center lead from the voltage regulator (this is the one coming from the battery as seen in the wiring excerpt below and will be white with a red stripe.) You can operate the tractor for quite a while on a fully charged battery...and if when you do that the circuit breaker cycling is not happening then perhaps the voltage regulator is indeed failing.
318 charging circuit.JPG

2. if this circuit breaker cycling only starts when the PTO is being used -- measure the resistance of the PTO winding. When these windings fail, they develop internal shorted turns, so the nominal resistance of 3.5 to 4.9 ohms can be very much less and cause an over-current load condition.

3. the circuit breaker itself may in fact be failing and tripping at a much lower current than its rating. These 25 amp CD circuit breakers are not expensive and you should replace it if it original to the 28 year old tractor. When you do this, you may want to consider replacing the slip on terminals in the harness with ring type that can be nutted firmly to the circuit breaker threaded studs for a much more reliable connection than the early tractors. Later 318 models had the ring terminals. Here is an on-line site that has the breakers for under $7 -- but your local auto parts store may have some in stock without needing to pay shipping. Deere may have them as AM33621, but will be more costly (greenFarmParts.com price is about $18 Green Farm Parts: John Deere Parts Online at Discount Prices )

Hope this gets you started -- let us know what you find in your troubleshooting using the above points.

Chuck
 

·
Premium Member
Joined
·
3,966 Posts
There is a link to JD Parts in my signature as well as a link on how to use it. JD Parts can be your best friend when it comes to looking up parts and diagrams.

Looks like the regulator is #5 Part # HE191-1748

MP2531_________UN01JAN94.gif

Stator and Voltage Regulator (Onan MN B43G) (222001 - 420000)
CartkeyPART NO.PART NAMEQTYSERIAL NO.REMARKS
1HE191-1276Stator1(INCLUDES TERMINALS AND CONNECTOR BODY)
212H246Lock Washer30.190"
3HE813-0143Screw3
4HE821-0008Cap Screw1
5HE191-1748Regulator1VOLTAGE, (SUB FOR HE191-1275)
6HE338-2087Wiring Harness1(SUB FOR HE338-1655)
7HE167-0188Clip1
8HE323-1216Elec. Connector Terminal2
9......Terminal2(ORDER HE323-1257)
10HE332-2319Clamp1
CartkeyPART NO.PART NAMEQTYSERIAL NO.REMARKS
11HE323-1257Kit1TERMINAL CONNECTOR BODY (INCLUDES TE RMINAL AND HE323-1216 CONNECTOR BODY)
 

·
Registered
Joined
·
4 Posts
Discussion Starter #9
Voltage Regulator rectifier B+ center wire

Thanks ChuckV,
When the tractor started tripping the breaker, I did as you suggested and disconnected the center wire (B+) from the VR. Also as you thought, I was able to run it a short distance. I have a new voltage regulator on order.
I was wondering though if the stator was actually the cause? How could I test it?
 

·
Registered
Joined
·
1,668 Posts
Stator tests are detailed in the TM1590 service manual (highly recommend that you add this volume to your tractor library...) Here are some excerpts from that manual:
Onan stator testing.JPG Stator resistance tests for Onan from TM1590.jpg

Unless the stator winding is shorted to ground, it should not be able to trip your circuit breaker if the voltage regulator is good.

Chuck
 
1 - 10 of 10 Posts
Top