I have a 4wd Stiga Park with exactly the same issue...
Eric
Welcome
Your articulated Stiga is a very different animal to Surypap3's Cub Zero turn .
So apart from a broken belt or crud stuck in one of the pulley V's there would be very little the two drive will have in common.
Please start a fresh thread in the
Transmissions section so the readers can devote their entire attention to your problem.
Most of the people on there are in the USA so the time difference may cause a long delay in response times and of course Stiga's are a very very small part of the USA mower market so probably not many Stiga owners on the forum to start with let alone the Park Articulated model and even fewer with the much more expensive 4WD variant .
As such people will be looking at your symptoms and trying to fit them with know transmission problem, so saying "mine does the same " is of very little help .
So please give the most detailed description of exactly what your Stiga does when you put your foot down on the pedals .
IS yours a hydro model or a manual gear box one like my 2WD one ( that I am yet to fix ) ?
What sort of noises does it make when you let the brake pedal off ?
Can you pull the brake pedal up and if so does the problem go away ?
Does the brake pedal pulsate when you are moving ?
Is it the same in forward as in reverse ?
HAve you just repaired / replaced anything before this happened ?
Was it instant or has it been slowly getting worse ?
Remember we have nothing to go on but the words you type on the page so the more you type the better the chance of the problem being resolved