I have the Honda 50 on my M and it works fine it is light weight and plenty of power. The Honda 75 & 90 model is way too heavy for the Mac. If you want a bit more oomph get a smaller engine that swings a 14" diameter propeller like the Evinrude e-tec 60hp or the Mercury bigfoot 60 or Yamaha HT60 all of which fall into the aprox 250# weight range. There is a 90 hp engine in the 300# range and that is the maximum weight you should ever put on the transom. Too much weight aft will hinder sailing performance.