You will need to take it apart and look..Sounds like sand in the throttle housing for the twist or thumb control or in the slide..If its in the carb slide them it most likly got in the motor.Damage could be very little depending..If sand god into the float bowl then I doubt much if any got into the motor..It would have to get past the jet and that pretty small with out it plugging up..My buddys r did that and the cable was shot..for 200 and it runs I would jump on it...
You must be fast,because I was hauling ass when I past you!