I just bought a 1986 18 ft 371V 150 G T it has a 14 1/2 24 pitch Raker stainless prop with jack plate. it has very slow take off and the bow doesnt raise much at all when on pad. max rpm,s is 4700 at 55 mph (maxed out) I think the motor is to high cause i compared it to a boat just like it and it is 2 inches higher than his. how do you no where is right? also what type spark plug should i be using and what type gas is best? what is a safe max rpm? thnx for any info