tomh Posted July 28, 2008 Posted July 28, 2008 My ignition switch quit turning the starter, but the tractor would start by jumping the two solenoid terminals. After several hours of trying to digest the wiring diagram and wire colors that did not always match, I isolated the two ignition terminals with two jumper wires. There was current coming to the switch, so I connected a wire to the return terminal and ran it to the solenoid. Then I reconnected the switch and tried to start the tractor. The starter works fine, the generator light works and the headlights work, but there is no fire to or through the plug. Do any of you have any experience or thoughts about this problem? I thought that maybe I shorted out the magneto wire somehow, but I don't know how to check it. You guys have been great at bailing me out so far, and I hope you can pull it off again. I'm sure you can tell that I couldn't make a living as a mechanic, but it is fun trying to learn a little.
tec2484 Posted July 28, 2008 Posted July 28, 2008 I don't think you can hurt the mag moving wires around. First I would put all the wires back as they were, then check the safety switches out. the easiest would be the neutral safety switch under the seat. (mine is very touchy, the hydro lever has to be perfect for it to start) then the pto safety switch under the left side mine was knocked off once and it took me 20 min to find out what the heck happened. As far as no spark look at the kill wire running down to the points. I had one that the insulator was cracked on and sometimes it would run some times not. The easiest way to test a switch is run a jumper wire from one wire to the other.
D-17_Dave Posted July 28, 2008 Posted July 28, 2008 You can burn out the windings in the magneto by connecting 12vdc to the kill wire. Best thing is to disconnect the kill wire from the engine connection,(most likely at the insulated block on the points cover) and diagnose the ignition circuit by it's self. Then return to the cranking issue.
wilm169 Posted July 28, 2008 Posted July 28, 2008 Yep Safty switchs first, then I have found the switch wires with a lot of rust on them, not making contact.
BLT Posted July 29, 2008 Posted July 29, 2008 Also, igition switch itself needs attention as it can get dirty and corroded.
tomh Posted July 29, 2008 Author Posted July 29, 2008 Can you be a little more specific about how to diagnose the ignition system by itself? Is there a way to test the magneto? The most pressing concern at the moment is to get the engine running again. The safety switch under the seat has been disabled for years. The starter worked once when I tinkered with the PTO safety switch, but quit when I taped the wires in place? Looks like that could be the source of the starter problem, but when I jumped that connection, nothing happened.
DMedal Posted July 29, 2008 Posted July 29, 2008 As Dave said, let's separate the ignition problem from the starting problem. If you disconnect the wire from the switch to the points at the points cover the ignition system will run separately. (It also won't shut off unless you ground this connection, turn off fuel, pull plug wire, etc. You know how to start it by jumping the solenoid, so next I think (as Dave said) sort out the ignition problem if any. turn it over with the starter and see if you have a healthy spark. Things that can still cause no spark in this configuration: 1) bad condenser 2) bad points 3) bad wiring between coil and points (pinched wire or disconnected) 4) bad coil 5) flywheel key sheared. Once you have spark proceed to switch troubleshooting. You already know that your starter works by itself. Solenoid: the solenoid is just an electrically operated heavy duty switch. The big terminals short together when a voltage is applied to the small terminals. I can't recall the exact wiring on your 3416H but I'm thinking the interlocks are on the ground side of the solenoid coil, either way the interlocks are in series with the coil wiring. If you turn the switch on and IF all the interlocks are closed, the starter runs. Real Bad Things can happen with the interlocks defeated so make sure it is out of gear, mower PTO off, etc, etc. disconnect your solenoid coil wires (the little ones) temporarily. 12V on one side of the coil, ground on the other, and bang expect it to crank. If not, bad solenoid since you say starter runs when you jump it. Coil wiring back on. Now it is time to test the switches. Your 12V feed for the solenoid coil comes from the ignition switch. Find the wire that leads to the solenoid from the switch by following it back and watching colors. If you apply 12V to that wire and the interlocks are all in "safe" position, does it crank? If not, then you need to go through the interlocks. If any one of these is open it won't start, so one at a time go through shorting out the interlocks. Come back at this point if you've not had a sudden flash of success. And if you find it, come back and share that too. -Don
tomh Posted July 29, 2008 Author Posted July 29, 2008 I disconnected the kill wire at the points cover, tried the starter and still no spark. Since it ran fine before I started using jumper wires, it looks it's a problem I caused. I did have a short one time that was hot enough to burn my fingers, but I don't know what the wire was touching. As Dave suggested, maybe I did burn out the magneto. Could this also damage the points and condenser? Is there any easy way to check them, or do I just start replacing? I have replaced the points and condenser a couple of times over the years on a 3314 tractor, but I don't know how to get to the magneto. Any guidance would be appreciated. Thanks for all the help so far.
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