When you say it goes run-run-run-run...is it revving up? Like slippage? If prop is good....have you pulled the prop and seen if prop shaft is good?? Put the engine in gear and try to turn the prop shaft by hand. You could do this with it sitting in the front yard. Or take prop off and check the splines.
"But if serving the Lord seems undesirable to you, then choose for yourselves this day whom you will serve, whether the gods your ancestors served beyond the Euphrates, or the gods of the Amorites, in whose land you are living. But as for me and my household, we will serve the Lord.” Joshua 25:15