Same thing happened to me. Turned out to be the brass ends at the Morse control. I couldn't get the control through the opening in the panel so had to unscrew the panel, shimmy it out a bit, and reach behind. Check my thread here: https://forum.supraboats.com/showthr...-ASAP-in-Maine

Skidim has these parts. Also unhook your throttle cable at each end and ensure it moves freely with little or no resistance. If it's tough to get through the full range of motion then check for sharpp bends and lube until it does or replace it.