While operating at full throttle yesterday, my '61 evinrude 10hp sportwin suddenly revved up and i lost power, so i throttled down (expecting cavitation) but each time i powered up, the motor screamed but with minimal power. It would still go but no power. Lower unit is all new and oil was clean. Now heres the Q's: Is the brass part inside of my prop separate from the prop itself? I thought that the shear pin protected the prop from damage, but theres actually 2 lines of defense here? I locked it in gear and could not turn the prop. I pulled off the prop and it looks fine. would'nt the shear pin go before the prop??? whats happening here? any help appreciated