They definatley can - there are no 170 worked services to Hull in the current timetable - TP only use 185s to Hull now.
Just to add a bit more detail to this, a TPE guard clarified the situation regarding 185s going to Hull a few years ago on this forum:
There are no particular problems, other than that on the section of line east of Selby where there are differential (higher) speeds for sprinters, they can't run at the sprinter speeds - unlike the 170s. They are given the same times in the schedule as their superior acceleration compared to a 170 means that there is negligible time differences between the two classes.
There are quite a few diagrams for 185's to Hull at various points during the day. The 1842 from Manchester to Hull is booked one as well for example.