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Discussion Starter · #1 ·
Hey all,
i have an electrical gremlin I'm hoping someone can help with. I have an old craftsman 2
Model #536.252570 that was starting 2 days ago but now only clicks. the only thing I did was change the deck belt so i shouldn't have mucked anything up?
I've been trying to chase it down with a multimeter and what I have come up with is that I have greater than 12V to the solenoid, and power transfers with the key as it should to through the coil. issue seems to be that I have no power to the stud on my starter motor when I turn the key.
on a whim i disconnected that wire and tested and get 12 some V, so that wire is energizing, but only when it isn't connected to the starter. i tried the starter off the mower, but no luck.
also should mention i did just charge the battery and it tests good, and the starter spins if I run power straight from the battery (i don't run the motor this way, just did a quick test to see if the starter would do anything)
any thoughts?
thanks
Hammer
 

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You have 12V to the solenoid. When it clicks, is there power coming out of the solenoid?
 

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Grounds, Batt to frame, frame to engine, engine to starter. I usually run a dedicated ground direct to the engine so not relying on just the frame connections.
 

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yup !!! first remove and wire brush the grounds and clean the terminals .....Second ...while trying to start it when you get the click , try tapping the base of the solenoid to make a better connection on the magnetic contact plate. sometimes it'll work , and sometimes it just totally not work !!
 

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Discussion Starter · #5 ·
You have 12V to the solenoid. When it clicks, is there power coming out of the solenoid?
good question, so to clarify, i have constant 12v to the solenoid terminal closer to the battery. only get 12v to the "far" solenoid terminal when I turn the key, as expected. I do hear and feel the click when I turn the key.
no voltage at the starter stud when with or without the key turned.
but when I disconnect the wire to the starter motor it that wire does get 12v only when the key is turned, but not when it is attached to the motor.

so I am thinking it is a ground short?
I tried taking the starter motor off, cleaning the top and the underside of the mount to make sure they made good contact but no change
 

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what you are describing ,to me ,sounds like it is the results of a dead solenoid . tractor supply , Napa, EBAY or Amazon. I've even grabbed one off the old Fords from when they used the same type of starter solenoid. For the sake of curiosity ,with the key in the on position , short out both lugs with a pair of plier handles or what ever you have handy ,and see if the starter engages and the motor start's if it does, then you know where the problem is.
 

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I suspect the relay is showing 12V when no load(starter) is present. Add a load, and the 12V goes to nothing because the relay is not actually passing enough juice to keep the V's up.
The 'jumper around the relay' test should demonstrate that the relay works or not. I have taken some apart by drilling the rivets, and flipped the copper(?) contacts inside. Many get pitted and burned looking, and likely don't make such good contact any more. Shining with abrasive or turning the contacts, or flipping the 'plate' bring better surfaces into working position. Nut and bolt the thing back together.
If you get a replacement, be sure to get the kind you need. Some use the chassis for ground, others have a separate contact/connector for ground.
tom
 

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Do the above to check solenoid problems.
Keep in mind it could also be the ground wire from the battery is not making good contact where it bolts to the engine.
I assume you have the battery contact end cleaned.

Could by pass that by clamping a battery jumper cable to a good ground place, clean bare metal, on the engine.
Other end on the battery negative. Then try to start with the key. If it works that way, then the negative connection needs to be cleaned, or negative battery cable replaced.
 
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Discussion Starter · #9 ·
ok, so I tried to jump both posts on the solenoid....nothing!
tried a jumper cable from the battery positive to the starter positive lug...nothing
following JP's advice I tried jumpr cable from battery negative to bare engine metal....nothing

to be clear when I say nothing, I am still hearing the solenoid click, but the starter doesn't respond in all cases.
I took the starter apart and it looks good to me, the copper inside looks bright, so i don't think it is burned out. when I took it apart I noticed that the lug on the starter has 2 nuts, 1 to hold the lug in place and 1 to hold the wire in place. the nut holding the lug in place seemed loose so when I reassembled I made sure it was tight. Now when i test with the multimeter I do see 12v getting to the starter when I turn the key, but still no starter response.

I can try taking the solenoid apart as suggested above, but i'd think if that was the issue (or only issue) i'd have seen action when I ran power straight from the battery to the starter, right? I did have that before I started digging into the starter, so maybe i reassembled wrong, but not sure what I did wrong since there isn't much to disassemble
 

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Discussion Starter · #10 ·
ok new info, just tested the starter OFF the tractor with jumper cables to the battery and it works great, just spins, no weird sounds or clicks or anything.
hope that helps?
 

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If you connect the "-" terminal of the battery to a non-painted bolt on the engine, and connect the "+" terminal of the battery to the large battery terminal on the starter motor, the starter will/should spark(BIG) and the starter armature should spin. The key switch and solenoid are bypassed and don't care using this method.
It is the same as clamping onto the starter with the "-" and touching the "+" to the starter terminal.(which you report works).
Jumpering across the relay, jumper cable to(connecting) the two large terminals on the relay(SPARK), should do the same thing as your above noted successful test. The "-" connections, at the battery and at the chassis, must be clean and tight, and the starter bolted tightly to the engine block. If that does not work, it may be the cables are damaged.
tom
 

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Discussion Starter · #12 ·
I want to start by saying a BIG thank you to everyone for their help, I got it running last night!
the funny this is that no one got it exactly right, but I never would have figured it out without your suggestions. turns out the issue was, though I cleaned the top of the starter to make sure it made good contact, it turns out I didn't do a good enough job on the underside of the engine mount.
found this out when i was testing for ground with the multimeter and realized that i missed that surface. got it scrubbed and a little dielectric grease and things work now.

thank you all again!!
 

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Based on what you said earlier, it's unlikely that that is the 'permanent fix', but glad you got it working to use it for the time being!

issue seems to be that I have no power to the stud on my starter motor when I turn the key.
on a whim i disconnected that wire and tested and get 12 some V, so that wire is energizing, but only when it isn't connected to the starter.
What that means is that something upstream of where you tested experiences a large voltage drop when you try to flow current through it. When Voltage pushes Current across Resistance, some of the Voltage or 'push' is consumed in the effort and usually converts into unwanted heat. That's called voltage drop and in general whatever it is you're trying to power, like the starter, should be dropping almost all the volts of the circuit and your wiring/switches/connections/etc should drop almost nothing.

Voltage drop is proportional to current, so if no amps flow, no volts drop. That's why you got 12v at the end of that wire when it was not connected to the starter, but did not have voltage there when it was. This would also allow you to measure voltage coming of the solenoid when no amps are flowing. The most likely thing is that the contact points inside the starter solenoid are in bad condition and making an intermittent poor connection. An easy way to test for this is to check for a difference in voltage between both big terminals of the solenoid. If the engine is currently starting, then most likely the difference there will be <2volts, because it's currently working. But once the tractor fails to start again, you will probably get a reading of 6-12v there, and that would reflect that that connection inside the solenoid has become most of the resistance of the entire circuit, and is burning up most of the volts (as heat).

The reason why i believe the ground was not your original problem is that if the ground had been the problem the entire time, you would have always gotten 12v at the starter wire whenever you tried to crank. The contact points inside solenoids can 'not work', and then you hammer that thing up and down a few more times, and the points beating each other up like tiny hammers will change the surface a little and then it will work. This is the same reason cars can get one loud click when turning the key, and after you keep trying and get that click a few times it magically starts and then keeps starting.. for a while..

So the most likely thing is you have a failing solenoid, may or may not have introduced some variables in the course of your diagnostic (like unbolting and rebolting the starter), fixed something YOU accidentally created, and by coincidence the solenoid beat its contact points into a workable connection again and made you think the problem you fixed was the original problem. This sounds like BS but as a mechanic i can tell you this crap happens to us all the time and that's why every mechanic knows what Murphys Law is and lots of other people dont! lol

So i'd throw a $12 solenoid at it anyway! Or wait until it acts up again and then check voltage across the big solenoid posts to confirm it, and then do it.
 

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It's not consistent with some tests that you already did but I once had situation of 12v to small terminal of the solenoid but the connection by keyswitch b terminal to s terminal was poor so you saw 12v but not enough current passed to fully engage the solenoid. Also a load test should be done on your charged battery.
 

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I want to start by saying a BIG thank you to everyone for their help, I got it running last night!
the funny this is that no one got it exactly right, but I never would have figured it out without your suggestions. turns out the issue was, though I cleaned the top of the starter to make sure it made good contact, it turns out I didn't do a good enough job on the underside of the engine mount.
found this out when i was testing for ground with the multimeter and realized that i missed that surface. got it scrubbed and a little dielectric grease and things work now.

thank you all again!!
larrybl suggested that in post #3 when he mentioned "Grounds, Batt to frame, frame to engine, engine to starter."

Can't get much more explicit than that.
 
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Discussion Starter · #16 ·
larrybl suggested that in post #3 when he mentioned "Grounds, Batt to frame, frame to engine, engine to starter."

Can't get much more explicit than that.
yes he totally did, and I cleaned the top of the starter, but neglected to clean the whole underside of the engine mounting point because I couldn't see it well. I did scrub it, but guess i didn't do a good enough job the first time. It's on me for sure, i just didn't get down low enough to check thoroughly.
 

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Discussion Starter · #17 ·
Based on what you said earlier, it's unlikely that that is the 'permanent fix', but glad you got it working to use it for the time being!



What that means is that something upstream of where you tested experiences a large voltage drop when you try to flow current through it. When Voltage pushes Current across Resistance, some of the Voltage or 'push' is consumed in the effort and usually converts into unwanted heat. That's called voltage drop and in general whatever it is you're trying to power, like the starter, should be dropping almost all the volts of the circuit and you wiring/switches/connections/etc should drop almost nothing.

Voltage drop is proportional to current, so if no amps flow, no volts drop. That's why you got 12v at the end of that wire when it was not connected to the starter, but did not have voltage there when it was. This would also allow you to measure voltage coming of the solenoid when no amps are flowing. The most likely thing is that the contact points inside the starter solenoid are in bad condition and making an intermittent poor connection. An easy way to test for this is to check for a difference in voltage between both big terminals of the solenoid. If the engine is currently starting, then most likely the difference there will be <2volts, because it's currently working. But once the tractor fails to start again, you will probably get a reading of almost 12v there, and that would reflect that that connection inside the solenoid has become most of the resistance of the entire circuit, and is burning up most of the volts (as heat).

The reason why i believe the ground was not your original problem is that if the ground had been the problem the entire time, you would have always gotten 12v at the starter wire whenever you tried to crank. The contact points inside solenoids can 'not work', and then you hammer that thing up and down a few more times, and the points beating each other up like tiny hammers will change the surface a little and then it will work. This is the same reason cars can get one loud click when turning the key, and after you keep trying and get that click a few times it magically starts and then keeps starting.. for a while..

So the most likely thing is you have a failing solenoid, may or may not have introduced some variables in the course of your diagnostic (like unbolting and rebolting the starter), fixed something YOU accidentally created, and by coincidence the solenoid beat its contact points into a workable connection again and made you think the problem you fixed was the original problem. This sounds like BS but as a mechanic i can tell you this crap happens to us all the time and that's why every mechanic knows what Murphys Law is and lots of other people dont! lol

So i'd throw a $12 solenoid at it anyway! Or wait until it acts up again and then check voltage across the big solenoid posts to confirm it, and then do it.
Vigo,
you were right, took me a couple days to get back to testing this because after all the cranking durring testing I needed to recharge the battery, then was busy with other projects and kid's activities but I just tested each solenoid lead with a full battery and have about 12v on the battery side lead and only about 10v on the starter side lead.
so guess it's time for a new solenoid.

thank you again to everyone for you help and wisdom
 
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