I am getting confused (doesn't take a lot) doing the cross referencing for hydro filters for both of these tractors, as the results appear to be contradictory.
Ideally I would like to find a compatible Fram or Baldwin filter as these are easier for me to locate.
I believe the current filter in the HT23 is equivalent to Bolens part number 172-6450 which cross-references to a Fram PH2844 or a Balwin BT8301. Others have suggested a Fram PH16 or a Baldwin B163 and further lookups I have done suggest the HT20 and the HT23 use the same filter. Some of these filter have an anti-drainback valve and others don't, the HT23 filter hangs down so I would not have thought it is required.
Some help on the Bolens part numbers for filters for both of these tractors would be appreciated, confirmation of them being the same or different would be a bonus and if anyone can point me in the direction of the best match Fram and Balwin filter that would be fantastic.