</font><font color="blue" class="small">( it will die if I hold the forward/reverse pedal down with almost full throttle )</font>
Just a thought, and I don't want to sound like some responders where the exchange goes something like this:
Post: "My tractor won't start"
Reply: "What RPM's are ya runnin' at?"
But - since you're new to the tractor, and its a new Kubota (rare for them not to run right), I just want to make sure you know the deal about the hydro pedal not being like an accelerator pedal. In high range I can bog down my 5030 pretty easily by pushing the pedal down all the way with any kind of load on the tractor. Are you hearing a high-pitched moan coming from the HST? That would indicate that plenty of power is going to it, but it's trying to flow too much fluid for the power available to it, like starting a standard off in too high a gear.
At a given engine speed, range, and load, you can only push the pedal down so far before you start using up available power. Have you tried it in low, with moderate pedal?
I know this is a long-shot and you've probably tried all this, just wanted to make sure you were up to speed on this aspect of hydros.
Other than that, on a brand-new Kubota .... hmm, I'd be freaking out too. It's in its "shake-down" period when little gremlins can crop up, simple little things. Bad fuel, clogged/blocked fuel line, air filter in wrong, something restricting the air supply ... good luck, and please keep us posted.
John D.
