It probably won't harm your engine. But god help
you when it comes to replace the shaft or some other reason you might want to detach the two peices (align the engine). Don't worry about losing your shaft. I think you will have the opposite problem, I think you might never be able to get the shaft off. Its probably permanently rusted in place I'll tell you I had a 1980 Watkins that I needed to take the shaft off to put on a PYI Shaft Seal and the coupling was *unbeleivably* rusted. I spent two weekends oiling, heating, hitting the coupling and nuts and I got nowhere trying to get the coupling apart. Then someone stopped by with a Sawsall (sp?) and said "just cut shaft and then coupling bolts" and then whack the coupling off. I did that and I had the thing apart in less than an hour. At the time the new shaft and coupling (which had a special mechanism to ease off the shaft in the future) didn't cost that much, probably about $120 and was well worth my wasted time and effort.
