Cold blooded means lean (not enough fuel) when warming up. When an engine is cold it requires a richer mixture to run smoothly until it warms up. Cold blooded also relates to oil temperature and gearbox oil needing to come up to the correct temp for the engine and transmission to run smooth and shift properly.
Originator will know, best to ask him. What it reads to me is: "Does not overheat and serviced by someone who doesn't know what he's doing" H
Cold blooded engines don't start up right away. It takes a lot of time and pumping to start. Rough idle could be as simple as a carb tuning or could need a rebuild. Cold blooded and rough idle might have a timing and fuel issue that needs to be worked out.
