Have a cub model 1515 that keeps blowing fuses while it is running. It does it at only an idle. The two red wires going to the fuse both get extremely hot within about 30 seconds. The initial problem was hard to start. It has non adjustable valves. I have 12.6 volts at the battery and battery side of solenoid. On the starter side of the solenoid I am only getting about 6-7 volts. Tried another solenoid and same thing. Cleaned all terminals no difference. Tried jumping straight to the starter still hard to turn over. What else can I check?
#2
reynoldston
I can't understand what the starting circuit has to do with blowing fuses if it is blowing fuses when it is runing?
From what I understand this fuse is on the wire going from the ignition switch to the starter. Not 100% though. This wire becomes extremely hot while the mower is idling and fuse pops. Would the starter be drawing that much power and then not disengaging causing that wire to overheat?
Doubt it has to do any thing with the starting system. Does it occur when you have the PTO engaged? Follow the two hot wires and see where they go. Sounds to me like you have a short that only happens when the engine is not under torque. A wire is coming in contact with a ground as the engine slows. Look for a burnt or cut wire. Could also be a bad ground, corroded or loose.
I will check that. But here's the thing. Something is drawing too much power somewhere when I try to start it and the starter has a hard time turning the engine. Well this same starting system that is having problems that I can not find is also the same system the fuse is on. I know what you are thinking. The starting system is only to start it then it is bypassed while the unit is running. Well that would mean my mower was doing what it is supposed to do. But it's not. Whatever is causing the starting system to be weak is also causing the fuse in the starting system to blow. It is only doing when it is running. Yes it will do it when PTO is engaged but also when it's not. It has everything to do with the starting system since it is part of the starting system. I just don't know how to pin point it.
It is likely you have a short in the key switch OR in the wires From the switch in the Run circuit.
If you do not have excessive current with the key in the On position & engine Not running, then you have a situation than has a frayed wire touching the frame when the engine is shaking at idle... :smile:KennyV
Kenny is right check all the wires. I just reread your problem and this could be caused by a bad solenoid. You should be getting more than 6 volts off the starter terminal. The pull in coil could be bad allowing for current draw while running. I would also replace the key switch. Don't get frustrated. Electrical problems on tractors drive all of us (who are supposed to know what we're doing) to drink and sometimes it just takes a little luck and a lot of time. While your checking the wires, also check every connection for corrosion and being loose.
Y'all are being extremely helpful. I think I am over thinking the problem. Haha. Wouldn't be the first time. I will check the voltage in the run position with it not running. Just so I will know because I am trying to learn as much as I can....what exactly is fused? Doesn't it come from the switch? Where does it go for sure? Again thanks. I will check it in just a little while. I brought it to the fire station with me today.
Checked and there is no spike in voltage. Everything that is supposed to have 12V in the run position has 12.4 volts. Now this is a 3 post solenoid....the small terminal is a ground right? I know it is grounded to the frame but was curious about the small terminal.
Checked and there is no spike in voltage. Everything that is supposed to have 12V in the run position has 12.4 volts. Now this is a 3 post solenoid....the small terminal is a ground right? I know it is grounded to the frame but was curious about the small terminal.
Never have I seen any type internal combustion engine have the small terminal attached to ground...
The small terminal is where the Key switch, in the Start position applies 12 volts.
That is the coil winding for the solenoid...
:smile:KennyV
I think your trouble shooting technique May be at fault...
Are you measuring what is applied by the wire?
What is measured on the post? OR what you can measure with the wire attached to the post?
(naturally the post will measure to chassis ground because it is attached to the coil inside the solenoid... the other end of the coil is attached to ground.. there will be a couple ohms of resistance in the coil winding).
Red with white stripe wire coming from the ignition going to fuse then solid red wire going to battery side of solenoid....This is what is getting hot and blowing the fuse. All connections are good and found no frayed wires. While mower is running I am getting right at 14 volts at the fuse while wires are steadily getting hotter.
I still did not find a schematic. Just wondering though....on all the other threads everyone tells the people to make sure that they have 12V at the small terminal. My small terminal is grounded. What could be my problem?
Kenny told me it was the way I was testing it....well it would not matter which part I had it on whether the terminal or the wire end connected to the terminal I would still get 12 V. I can use my VOM and attach the black probe to the small terminal and the red probe to the positive terminal on battery and it shows 12v meaning the small terminal is a good ground.
Again... The small terminal is the coil winding inside of that solenoid. It has to have continuity to ground in order to energies.
You apply 12 volts to that terminal ONLY when the key is placed in the Start position. (measure this by Disconnecting the wire from the small terminal, & then check to see IF you have 12 volts on that Wire, ONLY when the key switch is in the start position).
If you measure resistance of the small terminal to ground ... It will 'Look' like it is at ground... BUT if you have a good DVM you will notice it is NOT actually at ground. It will show a few ohms of resistance... That is the resistance of the coil windings. a more meaning full measurement would show the 'L'inductance of the coil in Henries. but a good ohm meter can indicate if the coil is go/no go...
That coil will have nothing to do with any electrical circuit when the Key switch is in the run position... :smile:KennyV
Kenny thank you because that was what I was needing is exactly how to test that which makes perfect sense now.
Is my only option left to go into the wire harness to check for shorts or is there a better alternative?
I can start and run the mower now but still blows fuse and overheats the wires, which I have also replaced because they were melted.
#23
Edwards saw service
If that mower has a voltage regulator it could be bad. I had this same problem with a gravely convertible. The key switch plug overheated and melted after blowing fuses. Just throwing that out there.
This problem is very intermittent. I got on it to move it and the fuse blew as soon as I try to go in reverse. I put another fuse in to see if it would do it but nope. I drove it around the yard holding those wires in my hand and they never once got hot. I tucked the main harness back behind the battery and it started overheating. Which tells me possibly a short in the main harness.
How many terminal in total are there on the solenoid? 3 or 4 Three terminals should be hooked up as follows. One larger terminal from the battery. Second large terminal goes to the starter. Small terminal comes from the key switch. Four terminals should be hooked up as follows. One larger terminal from the battery. Second large terminal goes to the starter. Small terminal comes from the key switch. Second small terminal will go to ground or a safety switch.
although not 100% the book way, if the start is the only thing giving you problems, I would run a single wire form the ign. switch to solenoid. make it a clean install. If you go cutting into the harness, more problems could arise>
john
If the small wire is getting hot while the engine is running, changing that wire will not solve the problem. That wire should only carry current when the key switch is in the start position. If you have 12 V to that wire while the engine is running the key switch is probably bad.
I hate to ask this but could you have gotten the wrong switch or wired it wrong? Reason I say this is that there should be no current thru that wire while the engine is running. Many key switches look the same, but the terminals on the back of the switch are different.
This is the same part number same terminals. I checked that first. But that's initially what I was thinking. Since one side of the fuse goes to the battery side of the solenoid and the other side goes to the key switch. So when the key switch springs back to the run position then the fuse should no longer have 12V on it. Right?
You are correct. Pull the switch. A good switch should have the terminals labeled. M equals magneto S equals start B equals battery. Look on the terminals or the switch base. Would you send me the part number of the switch?
That should be a seven terminal switch used by MTD. Could be used on a Cub if it is built for them by MTD. Looking at the back of the switch with the angluar terminals up and the horizontal terminals down, here is the terminal ID's. Lower left = Magneto. Lower right = Battery. Second left = Starter. Second right = Accessory 1. Center = Lights. Angle left = Ground. Angle right = Accessory 2. You may not be using all of the terminals. Hope this helps.
