Thanks. Is it a homelite 25 or 30cc? Id say a Prather 275 or 280. My modified 25cc could barely turn my 275, i think a 270 would have been a little better (i didnt have one to try). A stock 25cc probably would have enough torque to turn a 275 and im sure a stock 30cc would have enough grunt to turn a 280. So it depends on the which engine you have and how its setup. Id say pick up a couple props and experiment with it.

You need a stuffing tube in your boat, i just used a 1/4" ID steel brake line. Then you use the flex shaft from your trimmer through this tube which connects to a prop shaft which runs through the strut at the back of the boat. Have a look for some pics. Lots of pics around of different strut setups.