Thank you for your input. One more question. When changing the prop on my O.S. 40 LA, I inadvertantly took off the backplate. Well, I put it back on, but it is not on evenly, or it is bent. When I am at idle, it is clanking against the engine. When I move beyond idle to higher rpms, it no longer clanks. How can I get the backplate off? It's being difficult.