I have a 1987 Johnson 30, it sat up for a few years in the garage in which this year I began to use it again. Well after cleaning the carb. it would idle fine, and in gear it ran fine up until half throttle in which it begins to bog back and will cut off if I do not let out the gas. I finally decided to rebuild the carb and replace the fuel line. After that the problem still occurred, the only way it seems to run full throttle if I choke the air by removing the hood and placing two fingers over the carb. Ive also made sure the jets were clean, the compression seems to be fine, and the fuel pump seems to be working correctly. Any ideas?