Losing power while trying to get on plane

I've been noticing that while trying to get on plane with the vista it struggles a bit with the port side engine. As I throttle up I get about half way and the port side engine seems to lose steam, not much but the port side rpm's drop instantly to around 3000 while the starboard side raises steadily and consistently until I get on plane. Basically the starboard side is doing most of the work until on plane. Once on plane both engines perform *as they should and cruise along very nicely. Now here's the thing, the engines never really sound like they are having a hard time and the rpm's are never at extreme differences, maybe 2-300 rpm apart, so I wonder if it could be a drive problem or maybe even a spun prop on the starboard side?
The engines are Volvo penta 5.0Gi's and the drives are volvo penta dual prop on a 2001 four winns 298 vista.