Sucked many rocks over the years... But when you describe "half" power, does the boat still get up on plane?

I once hit hard, sucking rocks and after cleaning it out I had about "quarter-half" power. Took it in to find I had screwed the computer up, about a $600 fix...

I've had my shaft shear off, but that just randomly happened when out fishing one day, that's about $800. Just chalked that one up to wear and tear over the years...

I can't imagine you fried your liner or dinged your impeller up too much from a few rocks... Although the grates are there for a reason, some bent grates aren't going to diminish power much. I ran mine for years with warped grates....

Does it appear to have about a credit card width space between the liner and impeller? If not, shim the impeller to where you have that proper gap.... Big problem with those smaller motors if that gap is much larger you lose proper suction... Personally, I think this sounds like your problem. The bigger motors are more forgiving, you don't notice that lack of power as much.... When you get down to two shims left on the bottom of the impeller, that's when I'd suggest a new liner...

Sharpening the impeller is easy, many step-by-step instruction guides on the internet...

Keith