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MTD Yardman wiring problem


medic31's Avatar
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06-06-05, 04:53 AM   #1  
medic31
MTD Yardman wiring problem

I have a MTD Garden Tractor 21hsp 46" with wiring problem. Mower is about 4.5yrs old and has ran without a problem. Turned key and had power to ignition light but nothing when start mode. Checked safety switches for seat, clutch, and deck with no problem. Removed ignition switch to possibly replace and had apparently a hot wire cross and burnt one wire. It appears to be a ground that attaches to a screw under battery plate and then runs to headlamp wires. I have schematic from manual and it doesn't show this wire. It is completely uninsulated (probably the one that burned). It may have been a green/black wire (unable to tell from burning). It appeared to be ran together with the green wire from the headlamp. Need help with that wire and what I should do from this point. Thanks for your help!!!

 
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06-06-05, 05:29 PM   #2  
medic31,

The wire you speak of is a ground. It most likley was not insulated anyway. Check it's connection to ground. Make sure it is getting a good connection to the frame. This connection will not show up as a wire run on the schematic. Grounds are assumed on schematics and instead it will be shown as a ground symbol. Also, look for hidden fuses that may have blown. Also, check the starter solenoid. This is where most starting problems are. Once you get back to square one you may have a defective switch. You can check your solenoid by bridgeing both terminals with a screw driver. If the engines rolls over you can assume your solenoid is deffective.

God Bless,
Dave237

 
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06-06-05, 11:03 PM   #3  
Did you change the switch before the wire burned? It sounds like the electrical syatem polarity was reversed...possibly the battery connected backwards, or the wrong switch installed.


"Who is John Galt?" - Ayn Rand (Atlas Shrugged)

God bless!

 
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06-07-05, 05:28 AM   #4  
medic31
Thanks Dave237 & Cheese for responding!! In reference question from cheese. I removed the iginition from the tractor and began to remove the plug. I removed a green seperate wire (possibly a ground?) before removing the plug. Then I laid the ignition down and it touched the side of the tractor and then poof there was smoke from electrical lasting about 5 seconds. This green wire I speak of appeared to have that (ground wire fused together. The ground wire went from there to the bottom of the battery plate and was mounted to a screw.) Is this possible?Then I unhooked the battery (I know I should have done this already). The battery was the same as it had always been when it ran fine. In reference to Dave237 response of "bridgeing" the terminals with a screwdriver to test the solenoid, do you mean simply touch both terminals with the same screwdriver? Sorry to sound stupid! Thanks again for your responses. medic31

 
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06-07-05, 08:52 AM   #5  
medic31,

Yes, bridge both the large post (one to + side on batt) (the other one should connect to the starter) with the same screw driver. There will be a small spark and your stater should turn. All you need do is just give it a touch and see if it wants to spin. This would indicate a bad solinoid or a bad switch. As long you know your switch and all safty switchs are good then it's most likely your solinoid. Do not touch the screw driver to any other surfice while doing the jump.

Hope This Helps.
Dave237

 
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06-07-05, 08:58 AM   #6  
Azis
I may be reading a bit more into this than is here but.....
Is it more likely the smoke was let out of the wires due to bare terminals on the back of the switch touching the frame...? Possibly with the key in and on...?

With the wiring intact, a way to check the key switch and solenoid...it should have 3 wires going to it. 2 big lugs with big wires, and one spade terminal. Using a jumper wire from the + side of the battery to this terminal should simulate the key switch in the start position and cause the engine to attempt to start. If it does not, then jump the 2 big lugs as mentioned with a screwdriver or similar...if it attempts to start (or turn over) the solenoid is good, if not it is bad or may have bad connections to + or ground.

You will want to replace the smoke depleted wires with fresh smoke filled ones

 
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