2005 3120 complete loss of power, acted like dead battery

[tcdiver]

Okay, this one vexed me for a half a day. Tractor lost all power, no lights, no gauges, wouldn't turn over, etc. It had been acting a little funny for the last year or so. Power would just drop off intermittently and come right back. No rhyme or reason to it but then it just stopped dead. Nothing. I was thinking battery or maybe bad alternator caused a dead battery etc.

Started troubleshooting and connectors looked good. Took the battery out and it tested fine. Couldn't test the alternator short of taking it out so i keep looking and started to check any electrical connections that could be tightened. After a lot of frogging around i checked the main battery line to the starter. There is a couple other small eyelet wires on that same bolt to the starter. It looked tight which is why i had already looked past it a couple time but when i turned on it, it took about a half a turn to tight.

Boom, tractor took off.

The reason i post this is because the bolt in question on the starter looked like it was tight but had vibrated just enough loose to cause this problem.

Very surprising but an easy fix. Don't waste a half a day looking for the usual stuff. Check that bolt first if this problem happens to you.

 

[Spindifferent]

Thanks for the info!

I'll keep this in mind for my 2005 3520 should it ever exhibit the same symptoms. How many hours do you have on the 3120?

 

[tcdiver]

Low hours, just under 200. I use it mainly for cutting grass and brush on ten acres i have a cabin on.

 

[Deere Dude]

I have a 3720 and just around 600 hours the tractor wouldn't even turn over like everything was dead. It was the battery. Most of the time with batteries things get sluggish for a month or so, but not this one. Just dead.