Wayne_H
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- John Deere 4400, '48 B and 318
Can you get 12 volts to energize the solonoid and see if it engages?
Wayne
Wayne
deere 755 won't crank over
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update...still no start...replaced the ground cable with a new one. I still have all lights working, the clicking sound. glow plug light turns off correctly. Because I hear the clicking sound, I'm, assuming that the neutral start switch and other lockouts are not a problem. I tried jump starting but with the old grounding cable. Now that a new one is installed, I'll try it again to test the battery. If still no crank, how would I proceed from this point? I'm not super literate on posting pictures, but I believe the starter solenoid is beneath and a part of the starter motor on the 755...John
Wayne_H
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Sorry, I'm confused. Why did you replace the ground cable??
Is the solonoid on the starter energizing, and if it is, what is the voltage on the starter when it energizes? If it is not energizing, you need to figure out why. The glow plugs will do their thing if it is in gear or the PTO is engaged, the starter won't.
Wayne
Is the solonoid on the starter energizing, and if it is, what is the voltage on the starter when it energizes? If it is not energizing, you need to figure out why. The glow plugs will do their thing if it is in gear or the PTO is engaged, the starter won't.
Wayne
Thanks for your diligence Wayne. I replaced the ground cable because two thirds of it was frayed. I have a friend with a 4300 coming here tomorrow morning. It appears that the solenoid and the starter are part of a single unit. We'll check the voltage on the starter wire, and also try to figure out a way to fire the solenoid directly with going through the key switch. We're wondering if the wire leading from the key switch in position 2 is the problem. He still has his eye on the start /neutral switch as the problem. Apparently on the 4300 the s/n switch has a transistor so it won't work even if jumped out. The 755 is older and may be jumpable.
we're operating under the belief that the solenoid is the outlet for the red hot from the battery. So what we will do is jump start directly to the heave lug on the solenoid as the positive and the black line on the rear of the solenoid as the negative. This will hopefully show us if the problem is a blown key switch. If no crank, we'll try to jump out the start neutral switch. Coming back to the solenoid we has 12.5 volts to it regardless of the position of the keyswitch.
kebo
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Personally I would start back at square one trying to troubleshoot the problem. I've owned two JD 750's and the Yanmar engines on those were pretty similar to the one on your 755.
My first step would be to PULL the battery out, take it somewhere and get it tested. I would probably give it a good charge regardless whether you think it needs it or not. A fully charged battery should read about 13.8VDC with no load. So, when you put it back in and IF it does the same thing, then you have eliminated the battery as the cause of the problem.
Next I would double check all the major connection points on your heavy cables, both positive and ground wires, plus all the lighter gauge wiring to/from the solenoid and the ignition switch. Thoroughly clean as many connections as you can see while you are looking them over. If you see any in-line connectors, pop them loose and have a good look at the blades/pins. Sometimes they can get pretty corroded if a contaminate gets inside it. If the engine still won't crank, then you have pretty much eliminated the wiring and connections (with one exception I will get into later on).
The fact that you can hear the solenoid clicking tells me that most likely all of the safety interlocks are working correctly. If you heard no clicking when you turn the key, then I would say you would need to investigate all the safety switches/interlocks at this point as the potential cause, but that doesn't seem to be necessary in this case.
Since the solenoid will click when you turn the ignition key on to crank it, I think you can eliminate the ignition keyswitch. IF you heard nothing click when you turn it, then at this point you should measure the contacts on the switch with an ohmeter to see if they are closing. Since the contacts seem to be closing in your ignition switch, I think you can eliminate that as the cause of the problem.
That's getting down to just a few things left.
Before you do anything else, try this: Turn on the ignition key and HIT the STARTER MOTOR solidly with a heavy rubber mallet with the keyswitch on, or maybe use a small hammer. Just don’t hit it hard enough to break the cast housing. If the starter motor magically spins over, then you have the same problem I had on my 750.
You're correct that the solenoid is integral with the starter motor. I'm going by memory here cause I had to pull the starter off of my 2nd 750 and tear into it. It turned out to be ok actually, the starting problem I had with that tractor was an altogether different issue that I will go into in some detail below. If you must pull the starter off, then do it. It's not that hard, if I can do it I'm sure you can!!
The contacts are inside it on the end of the starter opposite of the reduction gear. When the coil is energized, the plunger slams the contacts together completing the heavy current path to the starter motor. Check these contacts, clean if needed. IF that’s working ok, and the contacts are in good shape, then its looking like the problem could be the starter motor itself. You can benchtest the starter with a spare battery, or a battery charger, just to see how well it runs by making the starter motor spin over while sitting on the bench. It's DC so it can spin either way, depending on how you connect it to the power supply. But, to be safe, you should connect it + to + and - to -. Also, watch for the motor to jump when you put 13 volts on it, it has a LOT of torque and it can jump off the bench if not clamped down good.
Anyway, to get to my last point the guy at the starter shop had seen my problem before. The solenoid on mine would click, but not turn the starter over (mine was doing the same thing yours seems to be doing). I told him I could bump the starter with a hammer (with the ignition keyswitch in the crank position) and it would spin over. He fixed me up an extra relay, told me how to wire it to the solenoid, and said it would fix it. Well, it worked like a charm and it cranked fine everytime after that. I’ve kept in touch with the current owner of that 750 and he says it still cranks with no problems whatsoever.
This problem was fairly common and is the result of some design flaws that are also seen in other tractors. It's a combination of wiring that was undersized, and poor connections over a period of time. To be more precise, some of the wiring on a good many JD tractors should have been made a bit larger. The undersized wire will increase the resistance of the wire and at the same time increase the voltage that is dropped across the length of the wire. Also, over the years the wiring connections can work loose, or just build up some slight resistance from light corrosion. On my tractor, these voltage drops (both in the wiring and in the connections) combined enough to decrease the voltage that was getting to the solenoid and starter. This would not let the solenoid slam hard enough, nor would the starter motor have sufficient current to spin the diesel motor over. Remember, this wiring resistance and any resistance in connections will drop the voltage slightly and at the same time will limit current flow to the components it's going to! When you’re cranking a cold diesel motor in the winter, you need EVERY amp you can get to the starter.
Hopefully by now you will have found out what's wrong with it! Good luck and let us know.
My first step would be to PULL the battery out, take it somewhere and get it tested. I would probably give it a good charge regardless whether you think it needs it or not. A fully charged battery should read about 13.8VDC with no load. So, when you put it back in and IF it does the same thing, then you have eliminated the battery as the cause of the problem.
Next I would double check all the major connection points on your heavy cables, both positive and ground wires, plus all the lighter gauge wiring to/from the solenoid and the ignition switch. Thoroughly clean as many connections as you can see while you are looking them over. If you see any in-line connectors, pop them loose and have a good look at the blades/pins. Sometimes they can get pretty corroded if a contaminate gets inside it. If the engine still won't crank, then you have pretty much eliminated the wiring and connections (with one exception I will get into later on).
The fact that you can hear the solenoid clicking tells me that most likely all of the safety interlocks are working correctly. If you heard no clicking when you turn the key, then I would say you would need to investigate all the safety switches/interlocks at this point as the potential cause, but that doesn't seem to be necessary in this case.
Since the solenoid will click when you turn the ignition key on to crank it, I think you can eliminate the ignition keyswitch. IF you heard nothing click when you turn it, then at this point you should measure the contacts on the switch with an ohmeter to see if they are closing. Since the contacts seem to be closing in your ignition switch, I think you can eliminate that as the cause of the problem.
That's getting down to just a few things left.
Before you do anything else, try this: Turn on the ignition key and HIT the STARTER MOTOR solidly with a heavy rubber mallet with the keyswitch on, or maybe use a small hammer. Just don’t hit it hard enough to break the cast housing. If the starter motor magically spins over, then you have the same problem I had on my 750.You're correct that the solenoid is integral with the starter motor. I'm going by memory here cause I had to pull the starter off of my 2nd 750 and tear into it. It turned out to be ok actually, the starting problem I had with that tractor was an altogether different issue that I will go into in some detail below. If you must pull the starter off, then do it. It's not that hard, if I can do it I'm sure you can!!
The contacts are inside it on the end of the starter opposite of the reduction gear. When the coil is energized, the plunger slams the contacts together completing the heavy current path to the starter motor. Check these contacts, clean if needed. IF that’s working ok, and the contacts are in good shape, then its looking like the problem could be the starter motor itself. You can benchtest the starter with a spare battery, or a battery charger, just to see how well it runs by making the starter motor spin over while sitting on the bench. It's DC so it can spin either way, depending on how you connect it to the power supply. But, to be safe, you should connect it + to + and - to -. Also, watch for the motor to jump when you put 13 volts on it, it has a LOT of torque and it can jump off the bench if not clamped down good.
Anyway, to get to my last point the guy at the starter shop had seen my problem before. The solenoid on mine would click, but not turn the starter over (mine was doing the same thing yours seems to be doing). I told him I could bump the starter with a hammer (with the ignition keyswitch in the crank position) and it would spin over. He fixed me up an extra relay, told me how to wire it to the solenoid, and said it would fix it. Well, it worked like a charm and it cranked fine everytime after that. I’ve kept in touch with the current owner of that 750 and he says it still cranks with no problems whatsoever.
This problem was fairly common and is the result of some design flaws that are also seen in other tractors. It's a combination of wiring that was undersized, and poor connections over a period of time. To be more precise, some of the wiring on a good many JD tractors should have been made a bit larger. The undersized wire will increase the resistance of the wire and at the same time increase the voltage that is dropped across the length of the wire. Also, over the years the wiring connections can work loose, or just build up some slight resistance from light corrosion. On my tractor, these voltage drops (both in the wiring and in the connections) combined enough to decrease the voltage that was getting to the solenoid and starter. This would not let the solenoid slam hard enough, nor would the starter motor have sufficient current to spin the diesel motor over. Remember, this wiring resistance and any resistance in connections will drop the voltage slightly and at the same time will limit current flow to the components it's going to! When you’re cranking a cold diesel motor in the winter, you need EVERY amp you can get to the starter.
Hopefully by now you will have found out what's wrong with it! Good luck and let us know.
Wayne_H
Gold Member
- Joined
- Dec 16, 2004
- Messages
- 380
- Location
- Davidsonville, Maryland
- Tractor
- John Deere 4400, '48 B and 318
12 VDC with all the current you should need is on the starter with that large RED wire. Yes, as I said earlier the starter has an integral solonoid. You need to see if that is getting 12VDC to it and if it clicks, what the voltage is now on that large red wire once it clicks. It could easily be a neutral safety switch.
Wayne
Special thanks to Wayne and Kebo-the problem was in the orange wire from the keyswitch to the solenoid. We got signal at the switch, couldn't see it at the solenoid, and so we jumped and it fired up. We put in a new iwre with a 10 amp fuse in it. We're working now on the hydrostatic linkage beneath the tractor. We get drift backwards and forwards when we shouldn't. Again, thanks to everyone for helping me at a tough time. We've been hit hard here with weather, and you helped get me through it. I'll pass the favor along to someone in your honor...John
Wayne_H
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Glad it worked out! Wasn't that easy??
Wayne
Wayne