# John Deere tractor model 970 diesel wont start



## ken970 (Nov 17, 2015)

John Deere tractor model 970 diesel wont start

Replaced the battery because there were no lights to dash. Was about time for change anyway. After replacing battery still no light to Dash. finally replace battery ground cable and that fixed the dash light problem. Plenty of juice to solenoid terminal.

now the engine tries to turn over. A rapid fire noise like machine gun when starting. But engine does not really turn over. the fan blades creep only. 

similiar to the sound of a weak battery but much louder now with the new battery.

since it seems like the starter is trying to engage what would keep the engine from turning over? 

There is no reason to believe engine is froze. Oil is good. Read something about compression release but not sure it applies here. Is that how a starter motor or solenoid sounds when goin bad?

p.s. just tried to start it using cables from my car after disconnecting battery plus on tractor. i jumperd right to solenoid terminal. Same exact symptoms as before.

Thanks.


----------



## Fedup (Feb 25, 2014)

Gear drive starters on compact tractors are well known for drive clutch failure. Starter will engage with ring gear and attempt to crank. Then the drive clutch lets out a loud grinding growl and the engine goes nowhere. Can sound similar to ring gear/drive gear teeth not meshing, but when starter is removed all the teeth look good, and starter will bench test good. 
You can have the clutch replaced for about $90 or so, or an aftermarket replacement starter for $85 and up. Some of them work out and hold up, others, not so much. You make the choice.


----------



## FredM (Nov 18, 2015)

That chattering you mentioned sounds very much like the solenoid is on the way out, the main contacts get badly arced (burnt contacts) and the solenoid wont hold.

If you are handy enough with the jump start cables, place the positive lead to the connection that goes to the starter motor and positive on the battery, place the negative connection to the negative battery post and then make a quick circuit with the other end of the negative cable to a clean area on the tractor chassis, when you earth the connector place a good amount of pressure to the earthing point, otherwise you will get some arcing. by doing this test this way, you are bypassing the solenoid and if the tractor starts, you will then see what the problem is, of course be very careful if there is any gas close by


----------



## ken970 (Nov 17, 2015)

Thanks for the replies. Thought I would have to send it to the dealer. Phew.

I guess I was concerned I got a bad battery (good voltage but no amps) or if not, something else I did not understand was wrong. For instance, I don't really know how a marginal solenoid sounds when failing if it sounds at all. When I tried to jumper if from my truck, I ran ground cable to the back of the tractor, could only reach the implement and ran another cable directly to solenoid. 

That was my mistake. Those connections must have been marginal, so nothing changed.

After reading this link http://www.yesterdaystractors.com/cgi-bin/viewit.cgi?bd=nboard&th=812716

So I decided to try again. I ran starter cables directly from battery ground to a point on the "engine" near the starter. And, another cable from the battery positive terminal directly to the solenoid (the starter posts are not available).

This proved that my "fix" for the poor battery ground previously was not well thought out. Since the original ground cable was somewhere behind the battery I thought I would just create another ground point. Unfortunately I selected to ground some half inch steel in front of the tractor, part of the bucket attachment. 

I guess it did not adequately connect to engine ground. Boy was that a dumb mistake. 

So once this is fixed I will only have a gator that wont start. What is all this telling me?


----------



## ken970 (Nov 17, 2015)

Fred,
Your suggestion would have got me there too. Thanks.


----------



## FredM (Nov 18, 2015)

Ken970

There is another way to bypass the solenoid, I didn't mention this before because there will be some arcing across the cable poles, for a start I assume your tractor is diesel powered, if gas powered proceed with caution, I am going to try and attach a photo of a solenoid so you will get the gist of what to do, you will see the two high amperage poles on the end of the solenoid, use a heavy screw driver or a cleaned up piece of 3/8" or 1/2" round steel, place either the driver or steel on one pole and with a firm push or touch make a bridge between the other pole, this will also bypass the solenoid and if the starter fires up the engine, your problem will be the solenoid.

As I mentioned before about the high amperage contacts inside the solenoid, if badly burned the solenoid wont hold, this comes about because there are 2 windings built into the solenoid, a light winding to initially pull in the soft core and make the circuit with the contacts and there is a heavier winding that becomes activated when the both contacts bridge together, as I mentioned if the contacts are badly burnt there will be no good circuit to hold the soft iron core in to the engaged position, hence the chatter you are hearing.

Most times if you hear just a click, this is from bad battery or dirty connections, you have seen to that part of the problem.

I must apologies to Mad dog for using his photo.

Hope this pulls you out of trouble and I would have mentioned this way to start the tractor if I had of realized that the machine was a little bit un-accessible to get to.

Regards


----------

