Guys,
This appears to be PRECISELY the problem my dealer mentioned on the L3800s. Evidently the gauge wire from the starter switch to the relay or solenoid is under gauge. It works for awhile but then, after harder start attempts, as in cold weather, the wire starts to break down. The dealer is running one new heavy gauge wire and they are having good results.
Now if heavier wire gets the job done, or the weaker wire will operate a relay to pull hot current in from a new wire directly from the battery, you are doing the same thing: MORE CURRENT TO THE STARTER. We all agree that grounds and cables need to be checked but, when those don't fix the problem, there is a work-around that might.
It takes about 30 minutes to break down the instrument cluster housing to get at the starter switch and wiring. I don't have time right now but, I'll check grounds and connections. That is easy. But, when I get time, this is the road I know I'll end up going down. And I will photo document it for this site.
The BIG question is this: Why is such a simple and essential circuit which has only been built into every car and tractor coming out of Japan for the last 65 years repeatedly deficient on successive makes and models of Kubota tractors? You don't hear about this in cars? Is it that many tractors sit out in weather (mine doesn't)? Is it not on Kubota's radar because it usually works a year or so past warranty before it screws up? This is a BIG deal for Kubota and they need to get the service reps out in the field to man-up and get the data back to the engineers so this problem is resolved once and for all. Paying $20-large for a tractor that needs re-wiring or recurring troubleshooting is not a good marketing strategy.
A tractor that is not reliable is a tractor of no value. Hear that Kubota?