How do I replace the PIN, SPRING 341, that hold the impeller 340 an allows it to spin?

Hi,
I assume that you speak of a shear pin even though I did not find them with those item numbers while I was at Sears, though it is acting up tonight. You would need to line the hole in the impeller up with that of the shaft and drive out the remnants of the old pin if it is still there and put in the new one.
Peace,
Clarke