Yup, wire core is nice but not required. Check the Links page at www.aomci.org or use their classifieds, I bet someone out there has the wire core rope. If you go with plain rope, heed FR's suggestion...and always carry a spare in the boat.
As a kid we used to get a ride with the neighbor in his Marthon racer with
a 1940s Evinrude Big Four 50 hp.Of course it used what we called a snatch cord to start and even with a compression relief it was a real bear to pull. You had to be ready for it to take off all most on plane.I can still see his perfect form half standing on one knee braced, 2 hands to pull and then skillfully catching the knot with his left hand so it didn't bite anyone. Turn off the compression relief set the spark and add throttle.What a ride 50+ mph in a time when 30 was a fast boat.And this was a big 16 footer that could carry 4 to 6 people.