JD 2640 Intermittent No Cranking

[Almonzo]

Hi Guys,

recently inherited my Dad's JD 2640. Have been having to jump start it; suspected very poor batteries (has 2), but now am not so sure. Topped off water in each cell of both batteries (almost 1 cup in each cell!), and they seemed to respond very well to recharging (bank reads now 13.6v, although I don't own a load tester to check CCA). Often previously I could get a weak cranking, before attempting a jump start with another vehicle. But despite the improved battery voltage, lately I most often get no cranking at all, although lights on panel come on, and headlights shine bright if I switch them on. While jump starting, I need to adjust the jump cables to fit on the battery posts, and at some point, I'll get a nice strong crank and it starts up. I'm thinking possibly starter solenoid or relay is getting sticky.

Wondering if anyone can suggest troubleshooting procedure to narrow this down, with some specifics on identifying wires/relay/solenoid. I do have the owner's manual, but not a service/repair manual.

thanks for any help.

 

[DLTTrekkers]

Check your neg toground cable at ground to chassis

 

[mike48130]

Check your neg toground cable at ground to chassis

Or connections to batteries. If you are jump starting, you are putting the power to the tractor cables and not the battery post, so it will start.

 

[Zebrafive]

1) Check/test batteries
2) Check battery connections, clean as required
3) If ground does not connect to the engine block (connects to battery box sheet metal) get a longer ground cable and connect it to engine block
4) Solenoid (on starter motor) can be rebuilt. Internal contacts may be burnt. They can be replaced.
5) John Deere offered a "starter relay kit" Your tractor may or may not have it. I think this is a field installed kit to help with starting problems.

 

[Almonzo]

Thanks, guys. Did some checking and had some success.
First, I think the batteries are slowly improving, with each discharge/recharge since I added water.
Second, I traced the negative lead down and found it is fastened already to the engine block.
Third, I used the "turbo" mode (250 amps) on the charger, for about 30 seconds, and got some hopeful sounding cranking. Hooked up another spare battery with jumper cables, repeated the turbo mode, and the engine started.
While I was connecting the jumper cables this time, I tried dragging the cable along the battery posts and connected terminal and noticed the sparks were rather weak, so it is likely the cable clamps and terminals could use some cleaning as well. They are also grayish, vs. the brighter color where the jumper clamps have scratched the lead, so they've probably oxidized a bit over time.

If any one knows where I could get a print or pdf service manual for this tractor, I'd sure appreciate it.
And thanks again for the suggestions.

 

[jaxs]

Fast charging will ruin a good battery. You should strive to recharge batteries as slow as possible(1 to 10amps) and a maintainer type charger pay's for it's self 10 times over in battery longevity. Wal-Mart and most auto parts stores load test free.

 

[Almonzo]

Fast charging will ruin a good battery. You should strive to recharge batteries as slow as possible(1 to 10amps) and a maintainer type charger pay's for it's self 10 times over in battery longevity. Wal-Mart and most auto parts stores load test free.

OK. I've currently set charger to 10A model, and it's charging both batteries wired in parallel. Thought about switching to using my trickle charger, but am skeptical it will recover quickly enough over night... we're needing the tractor more lately for snow removal.

 

[jaxs]

Half a gallon of water in each battery doesn't sound incouraging as far as batteries coming back up to full capacity. I would suspect a lot of sulfation as result of low electrolyte. Keep in mind that starting and/or attempting to start a diesel with less than full battery power is very hard on the starter. Point being that it will get worse before it get's better then you can wind up buying new batteries and new starter as the result of messing around with weak batteries. While we are talking about starter damage,the same applies to unusually long starts due to engine problems. Unless tractor is equipped with starting fluid metering,you best know exactly what you are doing before using it as a crutch.

 

[Almonzo]

I think you're right about the batteries. Looking at replacing with new, but wondering if anyone knows how many CCA is needed for reliable starting on this model? There's room in the battery compartment for various configurations of one larger or two normal batteries, so am wondering if single 1000CCA for instance could suffice over two 650's (the existing pair of batt's happen to be 24F group size).

 

[jaxs]

These tractors were cold natured when new. If you live in cold(you mentioned plowing snow) you need all the amps you can get. Since you already have 2 batteries,I suggest replacing with 2. Notice how cables are hooked and hook new the same way.