I have a '93 70 hp evinrude 2 stroke. It starts/runs well but after running for about 10 minutes the rpms/ power drops of to apporx. 1/3 max. In the past the rpms often picked back up after about 10 minutes. It no longer seems to be doing so.This problem has been intermittent but is becoming more regular. After sitting overnight the engine always starts and runs well for at least 10 min. the following morning (and sometimes the issue will not evidence itself at all.) Thanks for any ideas or further questions you might have.