I just bought a beautiful 1995 15hp 2s troke merc,it has 120lbs even compression on both cylinders but i was looking at the power head and saw spider like cracks,i don't know if it's anything serious or has many people seen this before so i need some major help here.I asked my 2 local marina's about this and they said it doesn't seem like anything to worry about.I don't know if it's just paint chipping cracks or if it's the start of something serious but my 2 local marina's told me that would be hard for it to crack there.They said it's nothing but i put pics up to get some info on here.I bought it off ebay so it was never told to me but i have never seen anything like that before,i'm hoping i can get some good news here.
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1995 15hp 2stroke merc power head issue or question
- Thread starter scoobeb
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From the picture, those look like raised bumps. If they are, then that is a blemish in the casting tool that is showing up. Do they show evidence of any raw metal in the cracks? If there is raw metal (not painted) at the cracks, then it could be something that occurred after the production of the motor.
From what I can see, these are raised bumps that are painted over, which means that it was cast that way. If this is the case, your marinas are correct and it is nothing to worry about. The sand casting process which is used to make these metal parts is a relatively inexact process. On top of that the "C" in the center of the circle is an insert that gets replaced routinely in the casting process, which would cause additional blemishes in the process.
The only thing to be worried about is if you see raw metal, which could be evidence of an overpressure. Since the 2 stroke uses the bottom side of the piston to compress the mixture, the entire crank case becomes a pressure vessel. If this is in an area of the cooling lines, it is possible that water was stuck inside the cooling area and froze.
But again, from what I can see, you've got a case where the company was trying to squeeze every bit of life out of the casting master before replacing it.
Good luck!
From what I can see, these are raised bumps that are painted over, which means that it was cast that way. If this is the case, your marinas are correct and it is nothing to worry about. The sand casting process which is used to make these metal parts is a relatively inexact process. On top of that the "C" in the center of the circle is an insert that gets replaced routinely in the casting process, which would cause additional blemishes in the process.
The only thing to be worried about is if you see raw metal, which could be evidence of an overpressure. Since the 2 stroke uses the bottom side of the piston to compress the mixture, the entire crank case becomes a pressure vessel. If this is in an area of the cooling lines, it is possible that water was stuck inside the cooling area and froze.
But again, from what I can see, you've got a case where the company was trying to squeeze every bit of life out of the casting master before replacing it.
Good luck!
I took some more detailed pics just so everyone can see,i took the lower plug out and look inside the power head were the cracks or wrinkles as you say,lol are and nothing seems to be going through the wall so i'm guessing you are correct as they are just cast markings.The compression is a dead 120lbs on both cylinders and i took the reading 3 dif times today and it never changed.Here is the more detailed close up as i can get pics.
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JMichael
Well-known member
I've had a few mercs and been around mercs most of my life. I've seen the same thing on a few different motors. It's just imperfections in the casting and nothing to be concerned about.
