I got hustled on my first boat purchase. I found oil in the water of my 1977 Merc 165. I immediately drained the block and manifold, did a pressure leak down test on the block eliminating the intake manifold from the system. I did have a couple of small leaks in the coolant hoses but it only dropped a few psi in a half hour and completely leaked down over night. I then plugged the hose in to the inlet, and my cylinders filled with water. I pulled the intake manifold and head to inspect for cracks. I found cracks in the front of the intake manifold. The head is solid, flat within .002, and i couldn't find cracks in the block. I need to inspect the cylinder walls. I also measured the position of each piston at TDC to check for a bent connecting rod, and all was good. I have got 1900 in the boat now. I need to buy a new manifold ~$500 and head gaseket set. I may replace my exhaust riser as well. Should this engine be rebuilt, or is there something else I need to check before I dump $700 back in to the boat. I am waivering on selling it for parts.
