Motor help please

[mamacyrus2]

We are new boat owners. We have a 97 suntracker with a 40hp. A few weeks ago we had a guy "fix" it. It was running rough and it would not go full speed. Most of the time when we went to put it in gear it would die. So we took it to this guy. He first did a compression test and came back good. Then he tore the carbs apart and replaced the gaskets. Also replaced the impeller(?). It ran good the first time we had it out. The next time it was out my husband said it seemed like it lost power and was bogging down. We haven't had it out since. We put the muffs on it last night and it seemed like it was running rough again. Can anyone help us? My husband knows lots about cars and such just not boats.