Yuku free message boards

Here's what I do when I'm helping someone set their carb on the 90/91. It wants to be as closed as possible on the radio needle but still have the lever in a position where it can be operated. I then do not touch the radio needle. I open the manual part of the needle about 2 or 3 turns. The metering needle is always set very rich from the factory and to set it I start the engine and blip the throttle to make sure it will rev up and then close the midrange half a turn, then blip the throttle again, I keep doing this until I reach the position where the rpm at idle starts to rise and then I close the midrange by very small amounts still blipping the throttle until the motor stalls when I blip it or open it up (if its too lean the motor wil start to race even on low throttle). I then back the midrange off by half a turn and that should be OK. Then run the boat on the water and gradually lean the full speed needle until it just starts to run cleanly at full speed. If the motor loads in the turns then the prop may be too big and/or the pipe is too short or the high speed needle is too lean. Slowing in the corners can also be caused by the float chamber (if its used) not being in the centre of the boat.