I am looking at purchasing a 2006 bay boat with a 2006 df140 motor with 60 hours. It is a 1 owner boat, by an older gentleman. I had the boat taken to a boat shop for a prepurchase inspection, and they told me it had low compression in the #1 cylinder and bad leak down in two cylinders. The compression was 155 in #1 and in the 170's in the other three. It also was not pumping any water, so they couldn't run it for very long, but they said it was long enough to warm up. They told me they would have to get into the engine to any further diagnosis. I know the boat has sat for a long period, and sat for long periods between each use. I also had them pull the exhaust plug, and there was not any corrosion on it. My question is this, could this be something as simple as carbon buildup from poor plugs and sitting so long, causing the low and inconsistent compression? Any advice would be greatly appreciated, thanks!