What exactly do I have here?

[JoshKeller]

Hey guys, admittedly I'm an omc guy, but got such a good deal on this boat that I couldn't resist. The cowling, motor bracket, etc all say mariner 150 (oil injected, which has been removed), but the powerhead says 200. Is this a 2.0? 2.5? Approx what year? It needs rebuilt as the top starboard piston has a hole from presumably running lean. Do the pistons say .030, etc if they are oversized? I see nothing on them except s and p which is presume to mean starboard and port. Thanks guys!

Serial numbers are.. Powerhead serial is ams09279w. Motor bracket is 5637220


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[JOE54]

2.4 LITER 200,most all pistons do say size on tops, that will be a chrome bore mtr any damage to bore will require sleeving or replateing, I got a bunch of stuff for that mtr/ powerhead

[JoshKeller]

2.4 LITER 200,most all pistons do say size on tops, that will be a chrome bore mtr any damage to bore will require sleeving or replateing, I got a bunch of stuff for that mtr/ powerhead

I came up with a 3.375" bore. Appears that's stock for a 2.4. All cylinders look good, I'm guessing the top cylinder ran lean. What rpm should I shoot for? Will probably replace the wrist pin, bearing, piston and rings. Go over carbs, check wot timing.