My 4hp aux is a long shaft (not XL - but a standard 4-6hp engine is short shaft) and it is fine on the transom of my Vipermax which has an XL shaft main engine. I doubt whether there are many XL shaft (25 inch) engines in this size range?
The only real difference on the Saildrive type engines is a fine pitch prop and sometimes a charging output to siphon off some electricity. May be just as easy to widen the search and change the prop?
A Boat is a hole in the water, surrounded by fibreglass, into which you throw money...
Sent from my Computer, using a keyboard and mouse