I've been running my Wyvern engine on Alkylate petrol. Although more expensive, this fuel doesn't go off with time (which is useful if you only use small amounts) and has a cleaner exhaust with no choking fumes. We had a thunderstorm this morning and I was optimising the engine carb in the workshop - I guess the engine ran for about 10 minutes all together. About a quarter of an hour later a piercing alarm which I've never heard before went off - it was the Carbon Monoxide monitor in the living room. Clearly enough CO had drifted out of the workshop, through the utility room, into the kitchen, through the hall and into the living room where the monitor sits on top of a tall bookcase.
Makes one wonder what the CO concentration was in the workshop. Just because there are no smelly fumes that does not mean that the combustion products can be ignored. A salutary warning.
Rod