After success with six John Deere marine engines, a charter fisherman adds four new PowerTech 12.5 L engines to his fleet. Steve Tomeny can't get enough of a good thing. Neither can his customers who come back to Fourchon, La., to sport fish for red snapper, king mackerel, and tuna on his John Deere-powered charter boats. In 1997, two of Tomeny's three charter boats, Louisiana and Gulf of Mexico, featured twin 300 hp 6076AFM marine diesels. His third, Southerner, was powered by twin 460-hp V12 engines of another brand. Because the hulls on all three boats were identical, Tomeny was able to make some interesting comparisons of performance and efficiency - comparisons that eventually resulted in the purchase of four 450 hp John Deere PowerTech 6125AFM engines for his boats.