I know the problem Wolfgang when in such a situation I rest my throttle foot up against the carpet on the side of the footwell to act as a tempory damper though it does wear the carpet in time but does give that part of my shoe a nice shine.. (-: I have seen the worn carpet to the side of the throttle pedal on some cars covered over with a shaped aluminium plate.
Some might suggest a stronger throttle spring but then that could become tiresome on the ankle in time..
That your Morgan seems likely to be a LHD, thus the carpet may not be as close to the throttle pedal as it is in my +8, you may require to adjust things a tad in order to achieve the same temporary damper arrangement...?
