Hey guys! I have a 1986 mercury 115 powerhead that burnt a piston rings. I then purchased a powerhead that claimed to be for 90hp and 115 hp. I installed the power head and took it out to try. It didn't have the top end o expected and will not rev passed 4700 rpm. The powerhead looks the same and I installed the carbs from the 115. Is there a difference with powerhead or can I use parts from the 115 to regain the hp.
