Boat has been sitting for a year due to flooding here at the lake, today I took it out the motor started right up. After we got past no wake zone, we started to accelerate - everything was OK for a while- I slowed down and then we I tried to accelerate after a few seconds it seemed as if the drive started slipping. The motor was running fine but could not accelerate more than a slow pace. Is there some sort of clutch in the out drive?