Having owned a few Adventures i would say the 150 Honda is a big lump for a 620, however i'm not a fan over evinrudes.
I owned tru blu 2 a 620 with optimax 150 and got about 39/40 knots reving to the max, When we first opened the school we Graeme Cooper had Topaz a 620 with Honda 130 this got about 35/36 Knots. However Cracker has got a 620 with Yamaha 100hp Four Stroke and this pull 36 knots no problem at all.
I would suggest in preference order
Mariner/Mercury 100hp/115hp four stroke
Yamaha 100hp/115hp four stroke
Suzuki 140hp four stroke
Mariner/Mercury Optimax 135 smelly two stroke
Ive got Crackers 620 in Pwllheli if its ok with him you would be welcome to take it for a spin just to see what the 100 yamaha goes like.