JD 310 diesel backhoe starting problems

[bigblue1949]

Starter clicks,clicks clicks,sometimes catches and starts.Friend told me it would be neutral safety switch,I bypassed switch same results.If I jump from battery terminal on starter and single wire terminal it starts right up.Is it solenoid,or wiring problem? switchs checked ok

 

[Jim.ME]

Welcome to the forums.

That sounds like a common problem where the switch doesn't supply current enough ton energize the starter solenoid. This can be solved by adding a cube relay just ahead of the starter solenoid. Use the wire from the switch to energize the relay and the relay load wire to energize the starter solenoid.

 

[bigblue1949]

would a new switch work?I looked at relays on ebay,they seem to have multiple terminals on them,wouldn't I need one with 2 terminals

 

[Jim.ME]

would a new switch work?I looked at relays on ebay,they seem to have multiple terminals on them,wouldn't I need one with 2 terminals

They have multiple terminals as they reduce the load on the switch. Yes you can put a new switch in and it may work for a time. the longer fix is the relay. JD actually had a bulletin and kit to add a relay. Wiring of a cube relay is minimal. they can apply 30 or so amps to the starter solenoid using low amperage from the switch.



Edited to correct spelling

 

[bigblue1949]

I'm no mechanic by any means.This is greek to me.There are only 2 wires I see going to starter.One from battery and one from switch,and I don't see how I could add relay.Only way I see is inline no mounting bracket of any kind,and vibration at some time breaking the wire to relay'Thank you for responding

 

[Jim.ME]

I'm no mechanic by any means.This is greek to me.There are only 2 wires I see going to starter.One from battery and one from switch,and I don't see how I could add relay.Only way I see is inline no mounting bracket of any kind,and vibration at some time breaking the wire to relay'Thank you for responding

The relay would be in line between the switch and starter.

Yes, you have to find/ fabricate a place to mount it. The relays are generally mounted less than 2 feet from the starter, so it is not a big wiring job. If you get a relay like the ones in my picture they come with a base mounting bracket and the wired connector. They are on eBay, Amazon and other places.

As the drawing shows:

You add the wire from the battery terminal of the starter solenoid to the #30 terminal of the relay.
Move the small wire from the starter solenoid start terminal to the #86 terminal of the relay.
Add a wire from the #87 terminal of the relay to the start terminal of the starter solenoid.
#85 wire goes to ground.
#87a is not used, just tape the end up.

This about as easy as it gets.

 

[a49deere]

Google 12v relays! a quick search showed a 40amp relay. This particular relay comes prewired, with one hole for mounting. 2 of the wires are the "switch" per say, the other two are the "coil power" that is energized and closes the "switch" when you turn the key to the start position. You don't need to do anything with the large battery cable. You will however need to remove smaller wire, and connect it to one side of the coil, the other side of the coil wire goes to ground. The other two wires are the "switch", one needs to be attached to the stud with the "Big" wire, or any other 12v+ source. The other is going to go to the stud that you previously removed the small wire from. The mounting hole could be tye wraped to starter solonoid somehow!

 

[a49deere]

Welcome to the forums.

That sounds like a common problem where the switch doesn't supply current enough ton energize the starter solenoid. This can be solved by adding a cube relay just ahead of the starter solenoid. Use the wire from the switch to energize the relay and the relay load wire to energize the starter solenoid.

I don't claim to be an expert by no means, just curious and trying to learn. What is your thinking on why the switch doesn't supply enough current to operate the starter solenoid. What kind of amperage does a solenoid need to operate? I thought the idea of the solenoid was to use low amperage to close a "Switch" to operate the higher amperage starter? I would think a typical max 15amp feed to the starter solenoid would be more than sufficient to operate solenoid! No? IMHO, i think all your doing by added a relay is creating another place to have potential problems. I would be looking at a worn out or faulty switch first. The contacts on the switch could/may be corroded causing this problem! OP never stated whether the battery was up to snuff or not either, another possible factor! Just my 2 worthless cents!

 

[Jim.ME]

A new ignition switch may work for ever or it may not. The pull in coil current for a Delco type 20 starter solenoid could be in the 30+ amp range, and 8+ for the hold in coil. A bit of wear or corrosion and the switch contacts lose some current carrying capacity as can happen at the neutral start switch and every connection between the switch and solenoid. True cleaning them may solve the problem.

Some heavy trucks and equipment have used an inline relay for years to reduce the current draw through the start terminal of the ignition switch, just as some use relays controlled by the ignition switch to turn buss bars that power accessories on and off, not running the accessories through the ignition switch.

.John Deere put out a service bulletin and relay kit to do this as they were seeing issues. Tx Jim likely has more info on this. I believe the original kits used a "Ford" starter type relay solenoid. The cube relays are readily available now and easier to mount in my opinion.

True bigblue1949 did not say the battery was up to snuff. He did post that using a jumper between the solenoid battery terminal and the solenoid start terminal, it starts right up. That is a sign of lack of power (current) from the switch to pull the solenoid coil in. A condition the relay can remedy, as it acts as a jumper wire controlled by the ignition switch.

I am editing to add that the larger starters (like the 30 or 40 MTs) may require using a "Ford" type starter relay solenoid for best results.