20FT SPORTCRAFT RUNABOUT 90HP JOHNSON.

THE BOAT DOES 22 MPH AT 42000RPM.
WHEN MAKING A SHARP TURN THE ENGINE
WILL SUDDEN RACE AT A HIGHER RPM, THE BOAT
STOPS IT FORWARD MOTION AS IF THE BOAT IS IN NUETRAL.

I MUST PULL THE THROTTLE BACK AND THEN MOVE IT FORWARD TO
GO FORWARD AGAIN.

IS THIS CAUSED BY THE LOSS OF WATER UNDER OR NEAR THE PROP

OR IS SOMETHING STARTING TO FAIL IN THE LOWER END OF THE JOHNSON
OUTBOARD ?