Randy Corson, owner of Liberator Boats of Florida has documented the performance of the first 21 Liberator rigged with the new 4.6-liter four-stroke V8 Mercury Racing 300R outboard. Corson has typically rigged this tunnel hull runaboat with a Mercury Racing 300XS V6 two-stroke outboard.
The Mercury Racing 300R offers 44 percent more displacement than the legacy 300XS and produces 40 percent more bottom-end torque and provides 25 percent quicker acceleration, according to Mercury Racing.
"The V-8 four-stroke produces so much torque that it demands a larger diameter prop," said Corson. "We saw 1.5 to 2 mph faster top-end speeds with the 300R compared to the 300XS with comparable props. The boat topped out at 106 mph, or 5 to 6 mph faster than the 300XS when running a 15.25 x 34-inch pitch Mercury Racing 5-blade CNC outboard cleaver."
The 21 Liberator also ran well with a combination of the 300R outboard and the MAX5, a Mercury Racing sterndrive prop that is finding success in select outboard cat and vee applications. Corson reports prop slip of just 9.7 percent and a top-end speed of 103 mph at 6200 rpm.