I recently bought a boat its a 18ft Tidecraft with a 115, it looks to me that the motor trims down to much, on takeoff with boat trimmed down it bogs as if its getting flooded and if i trim it up a little it comes out of the hole no problem? How can i fix this? My dad passed away 3 weeks ago and was a boat mechanic for 40 years, hes no longer here to ask so im asking for some opinions? 

Sounds like the float levels might be off. The was a very common problem for The early 92 to 95 Johnson 3.0. About the only way to get it to idle smoothly was to trim it level.

However, there are several other things but will need a more detailed info.