If all else fails, you could come up to Ponca with your boat and we could fish Kaw Lake in my boat while testing yours.
I have a 20hp merc on a smaller boat. We could try swapping props to see if it fixes your problem. I'd have to check, but think the output splines are the same.
Heck, even if I'm not having issues with the boat, that'd be fun. Likely the prop would fit.
It's not a shifter problem. More likely the prop.
A lower than normal prop can wash out like you describe or being an aftermarket it may need rebuilt or replaced.
I'll post what the tech has to say asap tomorrow.
If it's the prop go to Boat City Prop Shop 832 SE 44th in OKC.
Thank you, DFX. Sounds good to me.
Based on the fact it happens during a turn I would guess possible cavitation. Try lowering the trim pin one notch as I assume it doesn't have power trim.
I considered this, but haven't made a change. The boat had been running fine on the current trim selection, so I hadn't changed it. I'll give it a shot when I get a new prop (or mine fixed) on, to test.