saltwater block to fresh water

m2hunt

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Aug 10, 2008
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I am building a new motor what i need to know is what does salt water do to a block and will it hurt if i use this for fresh water
 

Don S

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Aug 31, 2004
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Re: saltwater block to fresh water

what i need to know is what does salt water do to a block

Salt water corrodes steel and iron a LOT faster than fresh water. Marine engines have brass or stainless core plugs, along with SS backing plates, special seals & bushings in the circulation pump, special head gaskets (not steel).
 

m2hunt

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Joined
Aug 10, 2008
Messages
21
Re: saltwater block to fresh water

i bought a boat with a bad block . I found a good omc 3.0 140hp block with a one pc rear seal. but the block was used in salt water. I plan on taking the internals out of the bad motor and put into the good block. I bought a marine rebuild kit
 

chiefalen

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May 18, 2008
Messages
3,598
Re: saltwater block to fresh water

Ok you can use it but i would confirm no hidden cracks with a magnafluxing.

Pay real good attention to the mating surfaces of the head, the water holes and the corners, make sure no holes are pulled up, use a magnifying glass. No cracks understand.Use the glass to check the sides of the holes on the corners, for a small crack maybe painted over, if you have to scrap the paint off.

The mating surfaces of the manifold. same thing. The holes not pulled up.

Ok every rod and bearing must stay together in the same position. Mark them with numbers or some other way. No turning the bearings same way you took it off the old motor is the way it got to be reinstalled.

I laid the motors side by side on a pallet maybe you have a better way and i did one at a time.

Get the torque values and use a torque wrench, this is a must.

Your gonna have off all the tins hold them up to bright sunlight see any pinholes, paint them 3-4 times before reinstalling them.

Good luck.
 
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