JD 314 garden tractor ignition system

NY 986 · Sep 4, 2023

In regards to the coil should the battery wire be hooked to the negative post on the coil? This is how the tractor came but running out of ideas as to no spark. Harness at key switch and switch were in poor condition so that stuff was replaced. The coil was tested. Some wear at points so those were replaced and new was installed per JD dealer instructions. Thinking about a wire bypass from coil to battery to see if battery wire has issues.

used red MN · Sep 4, 2023

I can only assume the machine has the battery in negative ground polarity, fairly rare to see a US sourced machine made after the mid sixties with a positive ground. Negative ground battery equals a required negative coil terminal connection to the distributor. So positive terminal of coil will be fed by power from the ignition. The coil will provide spark either way, but works performance is optimal with correct polarity. Hot wire to battery is a good step to test stock wiring of power to coil. I would suspect you have a test light. You should get an on-off flashing when cranking at the terminal of the coil lead going to the points if all is correct with the points. When the point close the light will go off if they are contacting properly.

wore out · Sep 4, 2023

Power wire from the ignition switch goes to coil's (+) terminal.

If it's the correct coil it does not require an external resistor, so there's no problem with using a jumper wire from the battery direct to the coil and starting and running it to check it out.

The electrical path from the ignition switch to the coil includes the PTO switch and the seat switch, so there's lots of potential problems that could be keeping the ignition system from getting power. I have a Technical Manual, but it's a paper copy, but I can get it and post a wiring diagram if needed.

On another note, once you get it running, spark timing is set using a timing light and varying the breaker point gap, which is covered in the engine manual linked below. (In .pdf format.)

Late timing can cause excessive engine heating and loss of power, early ignition timing can cause ''spark knock'' and piston damage, so it's important to set it correctly.

https://resources.kohler.com/power/kohler/enginesUS/pdf/tp_2379.pdf

NY 986 · Sep 4, 2023

The seat switch has been bypassed so that is another potential problem. New to me so the first priority is to get the engine
started to know if it runs with minimal issues. If the engine checks out then I will fix other issues as they arise. Counting
parts and gas to chase parts plus cost of tractor is now close to 200 dollars so if I get it running I have room to spend money on
it.

Geo-TH,In · Sep 4, 2023

Tractor Data
John Deere 314 Engine
14HP Kohler 512cc 1-cyl gasoline.
My money is that the coil (ignition module) is outside the flywheel and just like a lawn mower ignition module it uses the magnets in the flywheel to generate a spark. No 12v is applied to the coil. The wire going to the coil is the kill wire.

Did you use a voltmeter and measure any voltage going to the coil?

wore out · Sep 4, 2023

George, that Kohler engine uses a conventional ''battery ignition''/''Kettering ignition''.

There is a magnet and coils setup under the flywheel, but for battery charging only.

NY 986 · Sep 4, 2023

Update. I moved the wires so the battery wire hooks to the positive. I made a jumper to connect positive terminal on coil to positive terminal on battery. Engine started and ran albeit somewhat rough. Went to move knob for hydro block out. Would not move but did not have vice grips on me. Tried to start again but would not fire. Intermittent sparking of jumper on battery positive terminal. The condensor has a cob job not very tight mount so ground of it may not be the best. Oh well. At least it started once and the points move when being turned over. Enough for today outside.

JD 314 garden tractor ignition system

NY 986

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used red MN

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wore out

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NY 986

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Geo-TH,In

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wore out

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NY 986

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