312h Periodic no-start

[TeleSteve 2]

Symptom:  My 312h normally starts and runs with no issues. However, periodically I will turn the key and I get absolutely nothing. No lights on the dash, no clicks,  no attempt to crank.  I’ll turn the key several times and this scenario repeats. Then suddenly it will start as it is supposed to and runs perfect.  

 

Observation 1:  I had this issue yesterday and after several turns of the key I finally got it running. However I noticed that my battery meter was not functioning and none of my dashboard lights were illuminated (however, when I pressed the test button they all lit up).  I can’t recall if any of those lights are normally illuminated when the tractor is running. After turning off I tested the battery and have 12.6 volts - note:  the battery is 4 years old. 

 

Observation 2:  After shutting it off I could no longer get it started. I then turned the key to on and tried turning on the headlights. I got absolutely nothing - as if there were no battery connected. 

 

I found the wiring schematic on this sight and am ready to start diagnosing. Before I do that I want to see if anyone has experienced this issue and thinks I’m going down the wrong path. 

 

Could a failing stator have these symptoms?

Could a faulty ground cause intermittent no starts?

Can a seat sensor sometimes work and sometimes not work?

 

Thanks

[pfrederi 17,143]

Welcome!  Simple thing first pull back hard on the PTO lever and see if that makes a difference.

[TeleSteve 2]

Interesting you say that. My problems started when I removed my deck to install my blade. I had to release the PTO support bar to retrieve the belt. I forgot that I touched that area of the tractor.  Without that belt on it makes sense that the tension in general is going to be different. 

 

I will I’ll give that a try. 

 

 

[troutbum70 857]

Could be the ignition switch it self, next time it won't take a heavy straight from battery positive post to starter side of solenoid and see if it will crank up. Then start by passing safety switches and checking all connections. 

[TeleSteve 2]

Thanks for the suggestion. I started today by cleaning the battery posts and cable ends. Connected things back and was able to crank her up. I suspect that was just coincidence. I then tested the ignition switch leads for continuity. I actually found that my pink (volt meter) had a big cut in it. Soldered back together. That explains the bolt meter not working. The tan wire (PTO sensor) has a small nick in it but continuity was fine. I taped that one. Gonna see if I can recreate the problem. 

 

Thanks for for pointing me in the right direction

 

 

[troutbum70 857]

I would highly suggest the wire you soldered to go back and seal well with liquid tape and the same for the one you plastic taped, all the tape does is to allow moisture to get behind it and then corrosion will follow. and any wire fixes always solder and seal with liquid tape.

[TeleSteve 2]

👍🏻 Liquid electrical tape - I didn’t know there was such a thing. I just found it at WalMart.  I should clarify - I actually used that heat-shrink rubber tube tape.  Do you know if that is as effective as the liquid tape?

 

Pfrederi - I did try pulling on the PTO but I did it along with the battery cleaning. I’m not sure which (or if either) got me running again. I see on the schematic that the circuit needs to be open in order to activate the starter solenoid. I can’t find any documentation that states ‘what’ must be separated to give an open condition. There were no metal contacts visible. 

[troutbum70 857]

Heat shrink is very good, but a little liquid tape before the heat shrink is even better. I owned and operated my own semi tractor trailer for 40 years my last truck I had for 30 years. I was a nut for lots of lights my original harness was still on the truck when I sold it 2 years ago. I made good use of solder, silicon and heat shrink, I sold the truck to local meionite boys the harness is still working and lights still burning. I did change the lights about 8 years ago to LED'S.