reving up...62 lark 4

[ahdblo7]

i have a 62 lark 4 I was in the river yesterday puttering at a few miles per hour I increased the throttle the boat was going good I was going 15 mile per hour and then it revved up lost power could not go any faster so I throttled down I could go slow put now when I go to go fast it just reves up????

[Solarman]

Is it possible your prop is slipping? Or, is it jumping out of gear when this happens?

If you mark the prop where the cotter pin goes through the shaft nut, you should be able to tell if it is slipping.

If it is jumping out of forward gear back into neutral, and only stays in forward gear if moving slowly, then probably the drive & shift gears in the lower unit may be worn?

If it is revving up and staying in gear, but not moving, then I would think prop is at fault. Do you have a different prop you can try?

Good luck.