Should very well be possible. The Wright Flyer had an empty weight of 274 kg, and an engine that developed 12 hp, so you're way ahead there.
As for the propeller, you want the tips not to exceed critical Mach number because of the increase in drag for no gain in thrust, so tip speed needs to stay below 340 m/s. At max torque RPM of 2,500, your engine is doing 262 rad/sec. The drawing shows a prop with diameter 1.2m, resulting in a tip speed of 262 * 0.6 = 157.2 m/s or Mach 0.46. A bit low, longer blades would be better. No need to gear down.
It may be a bit impractical to use a propeller longer than 1.2m, best to use the largest standard diameter propeller that is still practical. Of course, the engine will need to be able to reach 2,500 rpm, where its maximum torque is developed. Required torque and thrust go up with RPM$^2$, torque goes up with $R^3$, thrust only with $R^2$. And this is the area where the Wright brothers made optimal use of the available horsepower, driving two huge, slow turning propellers.
An "educated" guess at torque & thrust here. I would say you'd need the longest standard size propeller that is your craft can accommodate without hitting the ground during TO/landing, with the highest pitch available.