Mercury F4 ML Sail 4 Stroke fits the well,I don't know if it would get into the cockpit locker .
Please don't ask any technical questions,all i know is I'am glad it has a reverse gear and uses an external fuel tank which gives better fuel presure for starting than the tank on the top.
I have it chained to the boat in Summer and use the local Police scheme of taking away the Engine Cover when leaving the boat, and replacing it with a loose cover from the Police. The Police have record of Serial Number etc from the Supplier and the idea is you can't buy a new Proper Engine cover unless you are the true owner.During Winter it is removed and Serviced by the Supplier and has been very good. I belive it is a long shaft.I have been using the Expensive 4 Star in it and not letting the fuel get too old.