I have a 2006 Honda 50 hp outboard motor. The Honda oil filters (part number 15400-PFB-007, black in colour) that I bought a couple of years ago only thread on about 3/4 of a turn before they contact the mating surface on the block. With the recommended 3/4 turn more to tighten, the filter is only hanging on by about 1 1/2 threads. This filter has a deep cover-plate.
Honda has another filter (part number 15400-PFB-014, blue in colour) that has a slightly shallower cover-plate -> 0.350″ versus 0.388″. The filter thread is 20mm metric fine. The .038′ shallower cover-plate allows for approximately one more thread of engagement – barely enough engagement in my opinion.
According to my local NAPA store, Honda filter part number 15400-PFB-014 crosses over to NAPA 1365. This filter has the correct thread AND it has a cover-plate that is recessed only .240″. This allows for several threads of engagement.
The Boats.net website has a parts list that shows a change from the -007 filter to the -014 filter at serial number 3015672, specifically for the Honda 50 hp outboards. Therefore, the -014 filter would be the recommended filter for my engine but the thread engagement is still marginal in my opinion. See boats.net for listings.
Disclaimer – I don’t know if the boats.net parts lists are official Honda lists?
THREADED FILTER MOUNTING “PIPE”:
After all of this, I wonder if the threaded filter mounting “pipe” is too short, or if it is recessed too far into the block. I haven’t determined if it is threaded into the block or pressed into the block