Is there a difference between these two solenoids?

[Jrblanke 840]

Hey guys,

Short story:

is there a difference between these two starter solenoids in the attached picture.

 

Here is the deal, I was trying to address my no start issue on my C120 (tractor has been sitting for about 15 years). 

 

I replaced the battery and all 3 cables before I began. Battery had 12.71 and was purchased today. When I checked voltage at the coil, It had 11.3 volts with the key on, but when I hit the key to turn it over, it would drop down to 9.2 volts while the engine was turning. I didn’t have spark. 

 

I decided I needed to take more wires off and clean the connections. When I removed the wire off the little post in the solenoid (going to the trans brake pedal switch) the post came loose. When I put the wire back on, it would not turn over or click. I decided to take it off and try this other solenoid I had (not new) and it then clicked, but would not turn over. 

 

Anyways, I was wondering if these two solenoids worked the same. 

 

Thanks!

 

 

Edited July 26, 2019 by Jrblanke

[prondzy 3,867]

No attached picture 

[Jrblanke 840]

Would one of the mods please move this to the correct section. I thought I was posting in electrical, not electric tractors. 

[McGrew 460]

All s solenoid does is to switch a high amperage load, taking that load off the ignition switch.  One solenoid may have a higher rated current, but electrically, they do the same thing.  Danny

[Jrblanke 840]

Danny,

Does it matter which direction the current flows? Like, could I hook the wires up backwards?

[McGrew 460]

Jrblanke, no, i do not believe it makes any difference on the large terminals.  You need to make sure the polarity is correct on the small terminals.  I only see one small terminal on the solenoid in your hand.  That one is grounded through the mounting plate, so it would be difficult to hook up backwards.  Danny

[squonk 38,936]

Most of those single wire solenoids ground through the bracket. Clean the mounting area. Others like a 701 ground at the small wire. Yes they can be different

[Pullstart 59,730]

I have ran dedicated grounds to solenoids with better success.  They ground through the cooling tins and then through the block.  

[Pullstart 59,730]

Additionally, the voltage going to the coil is through safeties from the switch and the solenoid circuit should not be a culprit, I.E. bad connections.  Once you get it to turn over, ty a jumper from th battery + to the coil and see if it’ll give you spark / run.

[gwest_ca-(File Mod) 10,499]

This page should help you understand how they work. Click on the picture and again on the next page.

Not all relays have the B terminal. These are wired internally so the base of the solenoid provides the ground when bolted to the chassis metal.

 

Garry

[adsm08 1,434]

These devices are more properly termed a "relay" than a "solenoid", although they do have characteristics of both. A relay uses low current to switch high current. A solenoid uses electrical power and electromagnetism to produce movement.

 

If you got a single thunk or click out of it the relay is grounded properly, is getting it's trigger power, and probably has worn or dirty internal contacts that are preventing it from passing the higher current needed to run the starter.

 

I'd start by testing the relay's ability to pass current by using a dummy load of some sort, a headlight is usually a good substitute. If that shows all is good, I'd use some jumper cables to try and run the starter directly off the battery and make sure it still works.

[Jrblanke 840]

Thanks guys! This is a great start! I am going to be out of town for the weekend but I’ll defi update next week!

 

[ZXT 2,394]

I would definitely clean all of the grounds you can find, and also clean all of the plug in electrical connectors as well. Due to the tractor being 40+ years old, there is likely some resistance built up in the wires. That being said, 9.2 volts to the coil while cranking isn't unreasonable. 

 

Have you cleaned the points or changed the condenser? The points would be the first thing I would check - this is done with the key in the run position, so it doesn't matter if the solenoid is working or not. After 15 years, they are sure to have some corrosion built up on them. File them, and if you still don't have spark, change the condenser. 

 

Since it clicks, It appears that the ignition switch is sending voltage to the small post on the solenoid. To see if the solenoid you're using is any good, jump from the small post to the battery lead. If it bumps over, the solenoid is good. If it doesn't, jump from the battery lead to the post leading to the starter. If it cranks over then, the starter is good but the solenoid isn't. 

 

The solenoid you have in your hand is known as a "Ford" solenoid. If that solenoid turns out to be bad, go to your auto parts store and tell them you need a solenoid for something like a 65 Mustand with a 289.. Should be less than $15. They're common as dirt.

[Sparky-(Admin) 19,550]

On 7/25/2019 at 10:11 PM, Jrblanke said:

Would one of the mods please move this to the correct section. I thought I was posting in electrical, not electric tractors. 

All set 

[bc.gold 3,399]

The top mounting bracket on the Ford style solenoid is your ground, connect a jumper cable to the engine to see if this improves ground. If it works with the extra ground you've found the problem, engine poorly grounded.

 

Ford style should be mounted in a vertical position.

 

Edited July 29, 2019 by bcgold

[Jrblanke 840]

Alrighty, here is the update.

Tractor still not cranking, and still no spark. I have not tried to address the spark issue yet. I put some better looking points on it, but haven't found my feeler gauges yet to set the gap. 

 

I replaced the solenoid and all the battery cables. I also bought a test light to help me understand what is going on. Here is what I have so far. 

1. With the key in the off position OR the on position, when I run a cable from the negative side of the battery to the little terminal on the solenoid, the engine turns over. I think this means that the solenoid (relay) is working, and also means the starter is working

2. When I touch the test light probe to the positive side of the battery, the light turns red. and if I touch the negative side of the battery the light turns green.  So with that in mind, I touched the test light the little terminal on the solenoid, the light glows red (regardless of the key position). 

3. I removed the wire that goes to the little terminal on the solenoid, and touched the test light to it with the key in the off and on position, and got no light. I then had my wife depress the brake, and turn the starter switch and the light turned red. So I took my volt meter and touched that wire with the key in the crank position (brake depressed) and got 11.75 volts. 

 

 

 

Edited August 2, 2019 by Jrblanke

[wallfish 15,921]

It's wired up backwards if negative is engaging the solenoid.

The solenoid should engage when positive is connected to the little post.

One big post connection should come directly from the positive side of the battery. The other big post should go directly to the starter post. The negative side of the battery should ground to the engine block. The solenoid mounting bracket must be grounded as well.

You should be able to "jump" a wire from the big post on the battery side to the little post and it should engage.

There should also be a smaller wire connected to the big post which comes from the positive side of the battery, this little wire is what goes to the ignition switch to feed power for everything else other than the starter.

 

Edited August 2, 2019 by wallfish

[Jrblanke 840]

Here is how it is currently wired. Seems to to be right?

 

Maybe where I have the ground going should be moved to somewhere on the engine, like you suggested. 

 

[adsm08 1,434]

The portion that grounds through the mounting bracket is pretty low current. If you have a grounding concern just run a small wire from one of your mounting bolts back to the B- terminal. 12 or 14 ga should be big enough.

Edited August 2, 2019 by adsm08

[Jrblanke 840]

21 minutes ago, adsm08 said:

The portion that grounds through the mounting bracket is pretty low current. If you have a grounding concern just run a small wire from one of your mounting bolts back to the B- terminal. 12 or 14 ga should be big enough.

 

When I hook a wire from the B terminal to a ground the engine turns over regardless of key position. 

 

 

[Jrblanke 840]

Ok, ran an extra ground from the battery to the back left engine mount, still nothing. I have a feeling I just have something stupid going on. Here is how I currently have it wired. @wallfish I think I have everything wired like you listed.

 

Cable from + battery terminal to solenoid big terminal D

Wire from solenoid big terminal D to the charging amp meter

Cable from solenoid big terminal C to starter

Cable from - battery terminal to ground near the gas tank

Cable from - battery terminal to left rear engine mounting bolt

Wire from B terminal to starter (through both safety switches)

 

 

 

Edited August 2, 2019 by Jrblanke

[bc.gold 3,399]

Anything happen when you jumper from the hot battery lead to the small terminal. Should engage starter.

 

IMO those battery cables should be switched, it was always the hot lead closest to the small terminal you could always jumper power from that lead to the small terminal to start a vehicle hot wired for ignition. Tin foil from a cigarette package twisted into a rope, screw diver or what ever was handy.

 

Also if you want to give your ignition coil an extra shot of power during starting run a wire  from the starter side to the coil, full 12 volts during start then revert back to the ballast ( internal or external resistor ) -  during run.

 

 

Edited August 2, 2019 by bcgold

[Tuneup 1,416]

Hi JR.

These are the first picks that show conclusively the battery polarity. You can buy them reversed nowadays at big box stores if you buy just by size and we don't know your level of expertise. So, now, the battery cabling to frame, engine and solenoid looks perfect. If you connect a DVM (+) to the solenoid live side and the frame or engine to the other (negative), you should get +12'ish.

 

OK, the ammeter is supplied with 12V - that's clear. We don't know if the other side of the meter is showing same. Mine was open and trash and that's not unusual.

 

Like was said, if you take a jumper wire and run it from battery positive or the live side of the solenoid to the solenoid start terminal, it WILL crank with a good starter and you'll see 12V on the starter side of the solenoid. This is as long as the solenoid is good, grounded to the engine and engine grounded to the battery. A good solenoid click will provide for 0'ish ohms on your meter across the power terminals as long as your battery is disconnected from those terminals - current affects the reading...

 

With a similar jumper to the (+) on the coil and all things from coil to points checked, the cranking will give spark on a good coil.

 

I hope this can help!

[adsm08 1,434]

18 hours ago, Jrblanke said:

 

When I hook a wire from the B terminal to a ground the engine turns over regardless of key position. 

 

 

 

I think you did it wrong. Hooking a wire to the engine tins from the battery negative post should not crank the engine.

[bc.gold 3,399]

SWAP the battery cables, on the solenoid terminals.