throttle adjustment

I have an issue with my 97 seadoo speedster. The issue is with one of my 717's. Its having issues starting..and when it starts, the rpms are maxing out at about 3.5k to 4k on full throttle. Why?

How do I adjust Throttle cables? Throttle levers at helm are all the way down but boat revs high and I noticed that the throttle screw is not making contact with throttle adjustment (lever) at mag side of carb. Seems I need to adjust throttle cable to put pressure on throttle screw to gain some...