Giving new life to a 1981 50hp Evinrude

[bonz_d]

Re: Giving new life to a 1981 50hp Evinrude

I'm still trying to figure out how to unblock this water passage. It's blocked in pretty thick. Any ideas? I'm trying to grind it, but I'm worried about hitting the mating surface between the powerhead and cylinder head since it's right there.

Pick up a round head or cone head deburring tool and slowly and carefully use it to drill the passage back open.

 

[ravihv89]

Re: Giving new life to a 1981 50hp Evinrude

So I went ahead and took a fine grit sanding block and scuffed up the surfaces of the passage to see exactly what was underneath that corrosion.

So my question then would be is it supposed to be blocked like that? It looks like it's part of the block, but it doesn't make sense because the thermostat is right behind it. Maybe I'm missing something? Also I'm confused because the cylinder head and the head gasket have a hole there. I can't find a diagram showing the cooling path through the block.

Any help is appreciated.

 

[bonz_d]

Re: Giving new life to a 1981 50hp Evinrude

OK. Let's back up a bit. Looked back through your pictures and this is what I've come up with.

1st get the cylinder head and the head gasket. Then lay the gasket on the head the same way it came off. Look at all the holes and watch how they line up. Next take the gasket and flip it over. I am going to bet that all holes match up the exact same way! What you think you are seeing as a passage really is not but just a remnant mark from the second hole in the gasket. Those two holes in the gasket are there so that the gasket can be used on either side. Otherwise meaning that one side is not up only.

Ckeck that out and see if I am right.

 

[ravihv89]

Re: Giving new life to a 1981 50hp Evinrude

OK. Let's back up a bit. Looked back through your pictures and this is what I've come up with.

1st get the cylinder head and the head gasket. Then lay the gasket on the head the same way it came off. Look at all the holes and watch how they line up. Next take the gasket and flip it over. I am going to bet that all holes match up the exact same way! What you think you are seeing as a passage really is not but just a remnant mark from the second hole in the gasket. Those two holes in the gasket are there so that the gasket can be used on either side. Otherwise meaning that one side is not up only.

Ckeck that out and see if I am right.

You're right. It never even occurred to me :facepalm:. Well just waiting on parts now.

 

[dicarlo]

Re: Giving new life to a 1981 50hp Evinrude

Looks like you have damage to your piston. Make sure you dont have any broken rings. Went through similar rebuild on my 100hp crossflow and when I pulled the head it was all pitted, similar to what I noticed in your photos.