[Christ]

It gums up the exhaust valves, but not so much that you can't clean the engine once in awhile to keep it in check.

I've run straight diesel in a gas engine. You need gas to start it, but you can switch it over afterward. It requires some minor carb retuning sometimes, and FI ECU's don't really like it, but it can be done. I've never advocated doing it on a normal basis, though. I've done it in a pinch, where I had diesel fuel and no gasoline. If I knew I couldn't get anywhere without fueling up, I'd put the diesel fuel in the gas tank while I still had some gas enough to keep the engine running. Cold starting a gas engine on straight diesel isn't fun, and you should have 2 or 3 batteries and a can of ether on hand if you want to try it. It's a PITA.