Sounds like a throttle cable adjustment at the motor. Loosten the strap that holds the adjusters and turn it (the adjustment wheel) a revolution or two, tighten it back up and give it a try. On the hose they run more RPM so the final adjustment should be made in the water. Nothing worse than a dock crasher. Just be careful not to over-do. Makes it hard to pull out of gear and awful hard crashing into gear. Recommended RPM is around 600 at idle in gear. If she is down at 400 in gear now she must be tuned just about perfect.
