Help-first boat first problem tach set up

[Greenjello]

Ok so I bought a 15ft procraft bass boat with a 25hp 2005 4 stroke bigfoot I like everything but I am concerned about too high rpms. First does the motor have a rev limiter, the motor will peg the tach, the tach only goes to 7k but the need moves to the limit of the gauge, upto what would be 8k. It doesn't sound like the motor is reving near that high. The tach is a teleflex looks to be newer than the boat so and looks to be in good shape I just don't know what is wrong. Do you know what pole setting the tach should be set on, are the teleflex tachs any good. At WOT the boat goes to 16.5mph which is at 8k which the motor doesn't sound close to be running at but I want to make sure and I want to get a better prop but need to get the tach fixed first.

Can anyone be any help do you know how many poles the tach should be set at or where to find that info