Scored Piston on a 70 Merc (oil injected)

d13mille	Does anybody have any info on a 70 hp Merc oil injected engine, 3 cyl. The problem is the top cylinder has a scored piston and the cylinder sleave has turned about 1/4 inch in the bore which now the port holes are partially obstructed. I've talked to some Techs and they say that a cylinder can turn if the engine should over heat. Also they said that this is common for those engines. The lower two cylinders look perfect. The engine did not run out of oil nor did the water pump fail as both of these items are working fine. My question is if the Tech I talked to is correct then there should be others with the same problem. Is there anyone out there with this problem. Because if it is I will not have this motor for long. Thanks	2001-11-06
12Footer	It is possable, esspecially on engines run in salt water, that the cooling circuit to that cylinder got an obstruction in it. The water pump would pump,just not cool that cylinder. Did it scorch or blister the paint around the area of that cylinder? If so, it's allmost for sure that is what happened. As far as the sleave turning,I have never seen or heard of that happening, but i do not doubt it...Just never heard of it before.	2001-11-07
nickster	I remeber a story that someone had told me, a long time ago. A gentlemen had told me that he had a hole rack of motors (Merc.) and every motor on the rack had the top cylinder out of it. I don't remember the years of the motors but I think they all were real close in the same years and in the same horse power. Like I said that I don't know to much about these paticular motors this guy had but they all did have one thing in common that the top cylinder was out of them. I hope this helps you Nick	2001-11-08

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