Re: many questions for new owner
I'll betcha JB's right about the noise. Often either the pull starter or the armature plate. You can try running it without the pull starter (wrap a rope around the flywheel and pull). The armature plate is the part that moves with the throttle immediately under the flywheel. If it's excessively loose, it'll make some nasty noise too.<br /><br />CD-24 is "officially" a 6hp in fact. After '64, the 5.5hp got split into the 5 and 6hp outboards. I think the main difference was the 6hp had reverse.

<br /><br />But it really does have it's roots in the 5.5hp. So that's not really wrong.<br /><br /><br />EDIT: Mostly, parts are easy to get. What isn't currently available from aftermarket suppliers and the OEM is easily found in the junkyard, online or ebay. You get into trouble when looking for oversized pistons, or a hood gasket, but even then a little hunting usually turns up what you need.<br />If there's a 5" long extension bolted between the lower unit and the midsection, then it's a longshaft. If that isn't present, then it's a short shaft.