hi there so i have a 55hp johnson on my 14ft boat the leg is too short and cavitates when i turn so i swaped it with a longer leg off a 50hp evinrude i took it out to the lake for a test run and i seem to have and exhaust leak from inside the engine cover where the adapter plate meets the power head and the motor doesnt cool... i used the evinrude adapter plate im woundering if i should have used the johnson one im new to boats so any info would be appreciated.