I just went through this when i replaced my fuel lines on a (very similar) YSB last month. none of the flexible lines are available from yanmar any longer, so i took my old fuel lines to a hydraulic shop and they were able to cut the old banjo fittings off so that I could reuse them. I bought some USCG fuel hose and made them up with hose clamps, but the hydraulic shop would have built new lines for me if i'd prefered.
At least for my engine, if you look closely at the yanmar parts diagram, you can find the part number for the banjo fittings new from yanmar. my dealer advised me that they were available but the price was high enough that I reused my old ones. I don't have a YSM parts list but here's an example from the YSB8; the double numbers in the diagram are for the YSB8/12 respectively.
The return line complete is no 25, but it also shows the banjo fitting as no 21 & the return hose as no 23. The detail:
Google results for no 21, "yanmar 104264-59030" give a bunch of sellers. The fuel hose and clamps are available at any chandlery. Note the size and length marked on no 23 as well.
Hopefully you can find a YSM parts list with a similar breakdown... but I suspect a hydraulic or injector shop can set you right without ordering expensive yanmar parts. good luck!
At least for my engine, if you look closely at the yanmar parts diagram, you can find the part number for the banjo fittings new from yanmar. my dealer advised me that they were available but the price was high enough that I reused my old ones. I don't have a YSM parts list but here's an example from the YSB8; the double numbers in the diagram are for the YSB8/12 respectively.
The return line complete is no 25, but it also shows the banjo fitting as no 21 & the return hose as no 23. The detail:
Google results for no 21, "yanmar 104264-59030" give a bunch of sellers. The fuel hose and clamps are available at any chandlery. Note the size and length marked on no 23 as well.
Hopefully you can find a YSM parts list with a similar breakdown... but I suspect a hydraulic or injector shop can set you right without ordering expensive yanmar parts. good luck!