Used EFI 4-stroke motors don't scare me. About the only thing that can be an issue with them is cruddy fuel which is easily remedied with a new filter, some fresh fuel, and your favorite fuel treatment. Perhaps one might require a siphon for really bad gas but that's pretty simple too. Gremlins don't scare me much either so long as there is reasonable access to the potential problems. 12V gremlins are actually REALLY easy to fix. You buy 100' spools of red and black wires and string, fuse, and label new wires anytime that the problem isn't initially fixed by cleaning up terminals and replacing a fuse or switch. The bigger issue for me is when one is required to hire a team of Romanian Contortionists to get at the offensive gremlin. Buried pumps, valves, and fuse panels piss me off.