Make sure on any of these models when you go to operate them that the lever for the Hyd remotes in the back is not engaged... it is a detent lever and does not line up with the N on the sticker when its in Neutral... very very easy to tell its lugging the engine if you have been around them for a while but if your new to the tractor I see it happen to %90 of customers... make sure the lever is in the middle position.. this will heat up your Hyd. in a bad way.. if left engaged to long it will burn every seal in the tractor..
the throttle response is exactly as you describe when its engaged.. may not be all of them but very common
the throttle response is exactly as you describe when its engaged.. may not be all of them but very common