860 starter trouble

Over the last weekend I put the 860 back together far enough to turn it over w/ the starter. All fluids in, wiring harness hooked up, plugs out & a little dash of oil in each cylinder. I turned it over a few times w/ the hand crank before installing the battery & starter. Turning resistance was about what you'd expect w/ the plugs out.

After installing the battery & starter it would just barely turn the engine over...very slow....then nothing but the dreaded "click" of the relay. My 1st thought was the battery(which has been on the shelf about a year); however, I've been pretty good about hooking the float charger to it about once every 6 weeks.

Temporarily ruling out the battery, I went back thru all my connections to make sure I was getting clean metal, plus I checked the starter/bell housing surfaces again. Still the same poor grunt & quit.

Just for grins I checked the battery state of charge again & it was way down....more than it should be for a few hits on the starter. That was enough for me to take it back to TSC for another battery. Their little meter said it was charged, but the CCA was down about 50%. I'm not sure, but I would think even 300 amps should turn over a 4 cyl w/ the plugs out.

I took the new battery & hooked it up to get the same performance. The only thing I can think now is the starter is siezed. I pulled the battery off & tried turning the engine w/ the hand crank again, but it won't budge.

So, it looks like I'll be using that spare starter rebuild kit I purchased for the 8N several years ago. Unless it's a short in one of the field coils or armature.

Anybody know the symptoms of a starter expiring well enough to make a diagnosis? Just for a little background, I started the tractor a few times when I brought it home. It had a 12v battery on it which spun it plenty fast, but I installed the new 6v battery, cables, & harness back then & it would start it, but really had to grunt. I passed that off to some rusty ground connections, but now I thinking the starter was on its way out.

Jeff

The most logical reason that the engine won't turn now is because the starter bendix is meshed with the flywheel. You had enough juice to kick the bendix out but not enough to turn the starter motor. Remove the starter, hook jumper cables from it directly to the battery and see what happens.

I hope you're right & it's that simple. I'll be very pleased.

If the starter is truly seized, you should see smoke coming from something. I think you've got a bad connection someplace. Hit the starter, then feel each of the connections between the battery and starter, as well as the ground connections. One of them is likely to be hot.

If that doesn't find your problem, get a voltmeter and check the voltage at various spots while holding the starter switch down. Wherever the voltage drops, there's your problem. If you find you have a full twelve volts from the starter post to ground, then the starter itself is bad.

Even if the starter is engaged with the flywheel, the engine should still crank over. A good starter doesn't need a "running start" to crank the engine.

There was no smoke that I could see or smell, but the starter stud was hot after holding the button down a couple of seconds.

I'm going to pull the starter off & clean up the mating surfaces again. I may pull the armature out & replace the brushes in any event. We'll see how everything else in the starter looks while I'm in there. All the other connection points have been double-checked.

Jeff

put her in 4th gear and rock her to / fro a bit.. might pop loose.

soundguy

A locked starter cant turn the engine,It does need a running start. the bendix spring takes up the shock.The starter used on the 860 wont disengage until the engine spins it out.There is a locking pin that retracts from centrifigal force.The weak battery engaged the drive but couldnt crank much.

You will need an obstruction wrench to get at one of the starter bolts and the oil filter is in the way if I remember right.

The 8n starter parts are different than the 860.Batteries should be checked with a hydrometer or load tested.

I'm no expert, but I had a similar problem with my 871 that required the starter to be rebuilt. The tractor is 12V, but the starter was turning the engine as slow as a 6V tractor. Also, it took a lot of charge out of the battery to get the tractor started. I disassembled the starter and found an area where the moving parts were rubbing. In addition to new brushes,etc, my starter needed new bushing(s) in the end plate.

HTH,
Mike M.

Coupe, I have to disagree with you. First, a DC motor generates maximum torque at zero RPM. Second, I know from experience because I've accidentally spun out the drive on my Ford's starter; I just reinstalled it in the tractor with the drive extended and it started right up.

anyone who has a locked starter will disagree with you .a locked rotor draws the highest current.

(quoted from post at 17:47:47 08/20/10) Over the last weekend I put the 860 back together far enough to turn it over w/ the starter. All fluids in, wiring harness hooked up, plugs out & a little dash of oil in each cylinder. I turned it over a few times w/ the hand crank before installing the battery & starter. Turning resistance was about what you'd expect w/ the plugs out.

After installing the battery & starter it would just barely turn the engine over...very slow....then nothing but the dreaded "click" of the relay. My 1st thought was the battery(which has been on the shelf about a year); however, I've been pretty good about hooking the float charger to it about once every 6 weeks.

Temporarily ruling out the battery, I went back thru all my connections to make sure I was getting clean metal, plus I checked the starter/bell housing surfaces again. Still the same poor grunt & quit.

I pulled the battery off & tried turning the engine w/ the hand crank again, but it won't budge.


Jeff

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Try turning the engine over with the starter out. You may have an issue with the rebuild locking the engine up. It would be a shame to damage the engine by accident.

WIth the starter out, connect it up with jumper cables and see how it spins. Or better yet, take it in to have it bench tested. I personally hate soldering in new brushes so much that I will buy a rebuilt vs doing it myself.

Yes, I was planning to hand-crank it over after the starter is out. I don't expect any problem w/ the engine, though. It has about 100 hrs(according to the seller)on it since it was rebuilt. I haven't started it for the last 3 years, so I put a little oil in each cylinder last week.

Jeff

Torque is directly proportion to current. The more current your starter is drawing, the more torque it is generating. As it speeds up, back emf reduces the voltage available to the starter, which reduces current and torque. Basic DC motor theory.

Do you know how torque the DC motor in a locomotive is generating when it is "locked"? A LOT. Which is why they use electic motors in big locomotives rather than mechanical transmissions.

(quoted from post at 17:16:46 08/23/10) Yes, I was planning to hand-crank it over after the starter is out. I don't expect any problem w/ the engine, though. It has about 100 hrs(according to the seller)on it since it was rebuilt. I haven't started it for the last 3 years, so I put a little oil in each cylinder last week.

Jeff

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Good! You're on the right track and will get it licked pretty quick. Having sat for several years, the cylinders could be rusted. That would make it real hard to turn for some time, I would put 2-3 measured oz of oil into each cylinder every day. Better would be a mixture of engine oil and ATF to help loosen up the rings. Just remember to crank it with the plugs out to clear the cylinders of any fluid. (it will smoke like a bug fogger at first from the oil, so don't worry about that. Probably for 5-10 min and there may even be a bit of greasy dribble sliding out the ex manifold. all normal from the extra oil.)

A locked starter drive and a weak battery will squash your theory,

Positive type starter drive locks in with a pin that releases when the engine starts.This starter drive was first used in the 52 Ford 6 cylinder.If you engage the drive with a weak battery the drive locks.A full charged battery can crank a locked drive some times.

I am requesting suggestions about how to remove the starter from an 860. The bolts are removed but the drive mechanism doesn't seem to want to disengage.