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Could running the motor as is "kill" it?
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It might not kill it, but it could end up costing a lot more to fix it! Here's an example . . .
I had a 1975 115 90 deg V-4 that I ran for over 30 years. They had higher compression back then and required 89 octane, which again was no big deal at that time. However I used to run in the Bahamas a lot, and gas over there is always questionable - you're lucky if someone hasn't dumped some diesel in the tank, let alone get adequate octane!
Instead of installing lower compression heads, I decided to just pull the heads and exhaust cover to clean out the carbon from head, pistons and exhaust ports. (This was before I knew about the various decarb products, but as Fr. Frank said, gaskets are cheap, and it's easy to pull the heads and exhaust cover on those motors!) This typically would drop compression from 130 to about 110, but I never lost any top end rpm, so evidently the benefit of clean ports offset hp loss from lower compression.
One year I found a light scratch in one cylinder and there were top ring cross-section impressions in top of piston and head! Turns out the anti-rotation pin in top ring land had come out, allowing ring to rotate into port area and break pieces off end of ring, which had also taken out a small secton of top piston land. Fortunately the scratch was light enough that honing removed it. If I had continued to run it, the scratch would have probably gotten deep enough to require boring. To avoid screwing up engine balance, if you have to bore one cylinder, you bore 'em all and install oversize pistons, so what was a $500 repair for one cylinder would have probably been over $2000 to bore/hone and install 4 new pistons if I had continued to run it! (And these were 1980 prices!)
One other thing I learned about that motor: unlike the 135/140 hp versions of same 100 cu. in. block, the 115 is not a "souped up" highly tuned temperamental engine. Consequently it always idled very well and would never die when maneuvering around the dock, etc. On a cold start, I could always move the fast idle lever all the way down IMMEDIATELY after starting. Turned out to be a pretty good engine test, because if it EVER died when I did that, there was ALWAYS something wrong, like a weak ignition coil or bad power pack, or a broken ring! It's like the engine was trying to tell me something! This may no longer apply to the new electronically controlled engines, but if you have a carbureted engine, it's important to learn what's "normal" operation and check out any changes from "normal"!