My brother wants me to test a 2004 Mercury 200 EFI Saltwater Series engine that he is thinking of buying. The engines I've owned and worked on are all spark plug and carb engines, 1 to 4 cylinders. I've never tested a modern engine like this, and it's a 6 cylinder. I normally check compression, test spark strength, and infrared thermometer the water passages for clogs and check other visible problem areas. In a quick Google check, I read that this EFI has electronics that can be analyzed with scan tools at the dealers. Should I just give the engine a quick look and if it looks and sounds OK, tell my brother to take it to the local dealer for a complete check?
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