24 volt starting problem

We have a 1961 4010 diesel. As we have posted and read on this forum it appears to have been correctly converted to the early 4010 system. We have installed new battery cables to the starter and a new fuseable link on the left side battery to the transmission and a new cable between the batteries. Now it turns over very slowly or not at all. The batteries are 8 months old and are holding a 12.4 charge. We have disconnected all the cables - then connected only the right hand side battery to the starter and the meter reads 0 volts, we then disconnect the cable and the meter reads 12.4 volts.
Any help in diagnosing this would be appreciated.
Also is the fuseable link the only ground cable on these tractors.

(quoted from post at 21:33:24 12/25/18) We have a 1961 4010 diesel. As we have posted and read on this forum it appears to have been correctly converted to the early 4010 system. We have installed new battery cables to the starter and a new fuseable link on the left side battery to the transmission and a new cable between the batteries. Now it turns over very slowly or not at all. The batteries are 8 months old and are holding a 12.4 charge. We have disconnected all the cables - then connected only the right hand side battery to the starter and the meter reads 0 volts, we then disconnect the cable and the meter reads 12.4 volts.
Any help in diagnosing this would be appreciated.
Also is the fuseable link the only ground cable on these tractors.

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"it appears to have been correctly converted to the early 4010 system"

Battery wiring as you describe started with 4020 Serial # 91,000, but, of course, many older tractors were retrofitted.

But, NO MATTER, from the point of view of the starter, ALL 24 Volt 4010 4020 systems are electrically the same.

As it left the factory, the (+) terminal on the RH battery was connected to a terminal stud on the engine side of the starter "belly".

The (-) terminal on the LH battery was connected to the large and topmost terminal stud on the starter solenoid.

So, measuring the voltage between the two studs just mentioned should give you a voltage reading of 24 Volts (nominal), actually around 27 Volts with good, charged batteries.



And, if your little ground wire/fusible link is intact, touch black digital voltmeter lead to a nice, clean area on the chassis, and the red lead to the battery cable stud on the starter solenoid, voltmeter should read (-) 12 Volts (nominal).

Now, touch red lead to other battery cable stud on engine side of starter belly, voltmeter should read (+) 12 Volts (nominal).

Check that out, and report back.

Your batteries should read 12.6 volts a rest. 12.4 is low.

Thanks for your prompt reply.
So, measuring the voltage between the two studs just mentioned should give you a voltage reading of 24 Volts (nominal), actually
around 27 Volts with good, charged batteries. This measured 12.4 volts

And, if your little ground wire/fusible link is intact, touch black digital voltmeter lead to a nice, clean area on the chassis,
and the red lead to the battery cable stud on the starter solenoid, voltmeter should read (-) 12 Volts (nominal). -12.4

Now, touch red lead to other battery cable stud on engine side of starter belly, voltmeter should read (+) 12 Volts (nominal).0
volts

Sounds like the RH battery is dead or shorted and isn't supplying (+) 12 Volts with reference to the chassis to the starter belly stud.

Go to RH battery and measure voltage at it's (+) and (-) posts with reference to the chassis.

Should "see" 0 Volts at the (-) post and (+) 12 Volts (nominal) at the (+) post with reference to the chassis.

Go to RH battery and measure voltage at it's (+) and (-) posts with reference to the chassis.

Should "see" 0 Volts at the (-) post and (+) 12 Volts (nominal) at the (+) post with reference to the chassis. If the cable is connected from + to starter we get 0 and 0. If the cable is NOT connected from + to starter we get 0 and 12 as you suggest.

Can you explain how BOTH the (+) and the (-) battery posts can read 0 Volts with reference to the chassis, if the battery is "good" and is "charged"?

At that point, what is the voltage between the two posts in the (RH) battery?

If the RH battery cable to the starter is NOT CONNECTED, we "see" 0 Volts at the (-) post and (+) 12 Volts (nominal) at the (+) post with reference to the chassis. 12 volts (nominal) between the two posts on the (RH) battery

If the RH battery cable to the starter is CONNECTED from the battery to the starter, we "see" 0 Volts at the (-) post and 0 Volts at the (+) post with reference to the chassis. 0 volts between the two posts in the (RH) battery

Keep in mind that the fuseable link is connected from the LH battery cable to the transmission case but no cables are connected to the LH battery posts

(quoted from post at 00:40:29 12/27/18) 0 volts between the two posts in the (RH) battery

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Sounds as if RH battery needs to be charged or replaced with a good battery

(quoted from post at 00:40:29 12/27/18) If the RH battery cable to the starter is NOT CONNECTED, we "see" 0 Volts at the (-) post and (+) 12 Volts (nominal) at the (+) post with reference to the chassis. 12 volts (nominal) between the two posts on the (RH) battery

If the RH battery cable to the starter is CONNECTED from the battery to the starter, we "see" 0 Volts at the (-) post and 0 Volts at the (+) post with reference to the chassis. 0 volts between the two posts in the (RH) battery

Keep in mind that the fuseable link is connected from the LH battery cable to the transmission case but no cables are connected to the LH battery posts

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"0 volts between the two posts in the (RH) battery"

If you are actually measuring "post-to-post" with no cable connections involved, as Jim says, the battery is DEAD or "bad".

While you are checking things, with BOTH batteries disconnected, grab your Ohmmeter and check for continuity to "ground" between the starter solenoid post and the "frame" of the starter and from the battery cable post in the "belly" of the starter and the starter "frame".

You should get an "infinite Ohms"/NO conductivity reading.

There IS NO continuity to "ground" between the starter solenoid post and the "frame" of the starter frame

There IS continuity from the battery cable post in the "belly" of the starter and the starter "frame".

The RH battery "post-to-post" with NO cable connections was 12 Volts (nominal).

The RH battery "post-to-post" with the cable connection to battery cable post on the starter was 0 Volts.

"The RH battery "post-to-post" with the cable connection to battery cable post on the starter was 0 Volts."

And what do we call a battery that measures zero Volts post-to-post?

The RH battery has 12 volts until the cable is connected. When we disconnect the cable it reads 12. We put the charger on it yesterday and it charged in a few minutes. All that being said we can change the RH and LH around if you think it is a problem.

You didn't comment on There IS continuity from the battery cable post in the "belly" of the starter and the starter "frame". We have suspected a short but don't know where to look.

(quoted from post at 15:34:16 12/27/18) The RH battery has 12 volts until the cable is connected. When we disconnect the cable it reads 12. We put the charger on it yesterday and it charged in a few minutes. All that being said we can change the RH and LH around if you think it is a problem.

You didn't comment on There IS continuity from the battery cable post in the "belly" of the starter and the starter "frame". We have suspected a short but don't know where to look.

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Well, a battery can't drop from some twelve Volts to zero when the cables are connected unless it's dead or defective OR there's a massive spark and smoke, and heating!

As to the starter, you didn't mention what resistance reading you got, but moisture and "brush dust" will provide an electrical leakage path from the innards of the starter that are supposed to be isolated from it's "frame" to the "frame"/"belly",
as will debris in the solenoid.


Or if it's a "dead short", the terminal stud could be shorted to the "belly", the field windings or armature could be shorted, something could be shorted in the brushholder or brush leads, etc..

Also, if it's the wrong solenoid (contacts and coils in this special style of solenoid are isolated from it's "frame, as well).

Disconnect the copper strap between the starter an solenoid and the wire between the starter and solenoid and check both solenoid and starter terminals to identify which has an inappropriate internal connection to "ground" and get an Ohms reading on it... dead short, or is there some resistance?


(I'd get the "grounded" issue of the starter or solenoid corrected FIRST, before replacing or swapping the battery, the short or leakage path will either discharge the battery over time, or "blow" the fusible link you have installed.)

Many thanks for all your help. It was a bad starter.

(quoted from post at 15:19:12 12/29/18) Many thanks for all your help. It was a bad starter.

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Glad you got it fixed, and that you let us know!

NOT sure exactly WHAT was going on, must not have been a dead short, or there would have been sparks and smoke, but, no matter, as long as it keeps working!