Carbureted or fuel injection?

How are your throttle cables looking and return springs (if present)? Any play?

Do you have PerfectPass? If so, is the servo motor behaving properly?

Definitely do not put it in gear if it is revving high - unless you are looking for more to repair.

Mine completely crapped out one night while towing a surfer. But completely crapped out - not a single light on anywhere. In a pitch black section of the river... Turned out to be a slightly loose main wiring harness plug. You might check not only for tightness and fully seated plugs but pull them apart and look for any corosion.

My PP servo motor also crapped out last year and had to be replaced. The joy of older boats!