JD110 Won't turn over

[dorlow]

I have a 70s John Deere lawn mower. I started mowing the lawn today and it was running rough... I thought the choke was a little off. Usually have to have the choke on for a minute, then turn it all the way off. It was hesitating like that for about 2 minutes or so. Then the tractor stalled. I went to start it and it wouldn't even turn over. (It turned over perfect about 3 or 4 minutes prior.) The battery in the tractor is brand new. I bought it about 2 months earlier...

So, I first assumed the battery somehow went stone dead. I hooked up a battery charger and it made no difference. Everytime I turned it over, I could hear a click coming from the engine.

After further diagnostics, I figured out it was coming from the starter or the solenoid. I took the lawn mower apart and got the starter out. I figured out there is a full 12 volts at the one post on the solenoid. The other post on the solenoid, I have a full 12 volts when the key turns over... to be expected. I then hooked 12 volts positive to the positive lead on the starter. I don't quite understand how the negative gets to the starter. There is no lead for it. I just made sure it was sitting on the engine. I figure the starter grounds to the engine. The other side of the negative from the battery grounds to the engine.

What I thought was odd though was when I hooked the positive directly to the starter and the starter sitting on the engine, I got a spark, which I didn't think made sense.

So, I'm pretty sure the starter is bad. If the battery went bad while driving, would that cause the lawn mower to stall? That's the only thing that makes me wonder if there's another problem... it stalled and was running really bad when I first started it. From what I understand, the starter doubles as the alternator or charger for the battery when it's running. Is that true? If not, how does the battery charge back up?

Next feat is to figure out where I can buy a starter for an old 70s John Deere 110 tractor.

 

[irwin]

I removed the starter from my 110, took it to a rebuilder, had it back the next day...

A good ground to the body of the starter is all it takes.. power to the stud.. if no starter operation.. yes it's got an issue.

My 110 has a magneto for recharging the battery.
There's a lot of info on-line for those engines.. poke around on the web...

Good luck

 

[dorlow]

I guess more of the question is, does everyone believe my troubleshooting is correct and the starter is bad, or is my troubleshooting flawed and there could still be something else wrong. It doesn't make sense why the lawn more ran bad to start and then stalled. The starter wouldn't' cause that. Or it was coincidence.

 

[irwin]

I guess more of the question is, does everyone believe my troubleshooting is correct and the starter is bad, or is my troubleshooting flawed and there could still be something else wrong. It doesn't make sense why the lawn more ran bad to start and then stalled. The starter wouldn't' cause that. Or it was coincidence.

You have the starter off.. with a known good battery see if it spins, then go on to the next diagnostic step.

 

[dorlow]

That's what I did. But when I hooked a positive straight from the battery to the positive lead on the starter, I actually got a spark, which I thought was odd. I just held the starter to the engine for ground. I think that's how the starter grounds itself. There is no negative lead. But with it directly to the positive lead on the battery, it should've just turned over endlessly. I got nothing.

 

[irwin]

When dealing with no crank conditions (no matter how many other symtoms).. we have to answer that first.. is the engine siezed? or is the starter bad and there are more problems?

#1: why won't it crank
#2: what you encounter once the engine cranks.

 

[dorlow]

I was wondering if the engine seized. I wasn't sure exactly how to tell that. But, right now, I'm pretty sure the starter is bad... but I'm far from being an expert mechanic... so I keep wondering if I'm overlooking something. I'm a computer tech. I see other people that don't have formal training try to fix a computer and they overlook very basic steps in my eyes... I'm probably doing this while trying to troubleshoot this because I'm not an expert. Granted the machine is pretty simple, so I can figure out mostly what everything is doing... but I'm not an expert.

 

[jenkinsph]

How much of a spark are you talking about? Recognize the starter is a high current draw device and you can get a spark when touching the lead to the post. A large spark may be indicative of a short in the starter. If you are still uncertain and it is removed I would run it thru a starter alternator shop as mentioned above, their reasonable in cost.

 

[CurlyDave]

The way I have tested starters, out of the vehicle, is to use a known good battery, usually the one in my car, and a pair of jumper cables.

The positive lead goes to the single pole on the starter. The negative lead goes to the body of the starter, usually the part that bolts onto the bell housing. Keep it away from the gear in there.

With no load, the starter will easily spin up to speed in a second or so if it is good. Be ready to remove the negative lead quickly if anything goes wrong.

 

[dorlow]

that's exactly what i did. i got sparks doing that... no turning over.