i have a 2000 sun tracker 18' party barge with a 2000 mercury 40 fourstroke bigfoot motor.today on lake i used my gps to find out how fast it would go. 14 mph was all it would do,the motor runs at 5100 to 5200 rpms and i have a 14 x 9 pitch prop.when i got home i took off the motor cover and turned the throttle full foward ,i checked to see if the carbs were wide open and they were not i could still push the carbs open a little bit more.can i adjust the cable ?or do i need new ones.i am new to boating and dont no much about it.
