You have an odd one when it comes to riders.
Remove the top engine cover and disconnect the single wire coming from the harness, that is a "kill wire" that is meant to ground the coil to shut the engine off.
Recheck for ignition fire. If still no fire, bad coil. If it has fire, it may be an issue with the key switch a safety switch or the wiring.
If a coil failure is the issue, this Kubota has an Onan engine and coils are not cheap, but there is a cheaper solution. Check out the following video by Teryll Fixes All around the 6:10-minute mark.
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