i have a 25hp johnson 1987 it would bog at wide open cleaned carb and all lines and tank checked compression a put in newplugs still same trouble i could cover the top left hole nearly and it would do great tried apluging it leaving a small hole and it would fly finally i tried ajusting the screw on the leftof the carb that moves the butterfly valve and it runs great now nothing on the small hole now simple fix im learning threw trial and erra thought some body may need to see this iant a mecanic