2005 175 hp optimax RPM's/Throttle Issues

[RedBeard0117]

Just bought used 2005 Ranger 185 VX has a 175 hp Mercury Optimax. It goes into gear no problem and will go into reverse but when I throttle up all the way the motor revs up but it does not increase in speed. I throttle down and ease back up still nothing after a few times of throttling up and down it finally takes off. If I am alone in the boat it will take off but still takes a little while (It did over rev when I was by myself). If I make someone sit in the front it will take off when I throttle up but it takes a little while as well. The motor will rev up every time I throttle up but it just won't take off every time I throttle up. It currently has a 25 pitch Tempest prop on it, any ideas?

 

[Chris1956]

It sounds like you are on the edge of available power for acceleration. Your prop may be a bit too high in pitch, but first, take a compression test and a spark test, and post results.