Larry,
On my S900, the preset panel organs under the Organ category, like Cool!Organ, Cool!FullRocker, DanceOrgan, etc. have a sustain about the same as a piano voice when the pedal is held down.
If I go to the Organ Flutes section, then the sounds like JazzDraw, PadOrgan, SixteenOne, etc. have a continuous sustain when the pedal is held down...in other words, the sound does not stop unless you release the pedal.
This works the same way on my buddy's PSR-3000, and another friend's PSR-9000 Pro.
Now, on my Tyros3, under Organ the SA JazzRotary, SA RockRotary and Cool!HoldItFast have a very short sustain...almost none.
The SA WhiterBars, SAProgRockOrgan, Cool!Organ (the latter the same as on the S900) all have a sustain about the same as a piano.
The Organ Flutes (or drawbar)section on the Tyros3 has a continuos sustain, the same as the S900's Organ Flutes section.
Seems the S910 may be using the same type of organ tone generator as the Tyros3 (and perhaps the Tyros2), albeit, with less choices, although I have no official confirmation from Yamaha.
Perhaps Steve D. from Yamaha USA would know more about it....have you contacted him?
.
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Yamaha Tyros4, Yamaha MS-60S Powered Monitors(2), Yamaha CS-01, Yamaha TQ-5, Yamaha PSR-S775.