1977 Mercury 850- water in all cylinders

[tallcanadian]

I don't understand. Cover the holes? Lol. I'm not too bright sometimes.

It's the first time that I really looked at it. They were drilled. Why would someone do that ? Just my luck.

 

[Faztbullet]

Someone thinking it would run better with extra breathing

 

[tallcanadian]

So today I got the baffle covers off. I broke two bolts. I guess that's not too bad? There is a lot of corrosion on the water cover but I don't see any holes. I even held it over a bright work light and can't see any pin holes or anything. Even on the exhaust side of the engine I cant' see where there could be water coming in. As a matter of fact, I don't see any water in the cylinders at all. I have to take a wire brush and scrape all the corrosion and soot off. I would have to say that I should look for other baffle plates because of the corrosion. Maybe you guys can let me know if I have to or not. Maybe this is all normal and I'm over reacting. I've included a few pics.





I also notice that on the engine that there is a lot of soot build up at the top cylinder, and as you go down, the better the engine looks, no build up. There is even a little burn on the top piston. The others look okay. Any info?

 

[Chris1956]

Well, the baffle plate looks to have 5 minutes of life left. The outer cover looks better, but hard to tell how much better. Check the outer cover for flatness, replace the baffle.

What does the inner cover look like? Sometimes holes hide in the nooks and crannies.

 

[tallcanadian]

That was going to be a question I was going to ask. Those 16 bolts, that's the inner cover? So that can come off too? It looks good but I will have to clean it up to see if there are any holes.

 

[Chris1956]

Those inner water jacket cover bolts were glued in by the factory. They are likely more difficult to get off, than the cover bolts. If it looks good, I would leave it alone.

 

[tallcanadian]

Thanks guys. I will have to clean things up to see better.. So I guess I better get on the hunt for a baffle plate. I know one cannot buy them. It does look bad and I wont put it back on. Can these be painted by any chance?

 

[Chris1956]

I have an baffle and outer cover from a '73 Merc 850, slightly used but in good shape. If it fits your motor and you want it, we can work something out.

 

[tallcanadian]

I have an baffle and outer cover from a '73 Merc 850, slightly used but in good shape. If it fits your motor and you want it, we can work something out.

Check your PMS

 

[tallcanadian]

I've been trying to remove the two broke bolts from the block with no luck. I've heated, penetrating oil. I bought a new pair of vise grips which are now bent. Anyone have any thoughts?

Also, I've included a couple of pics which look like cracks. I don't think it's my water in the cylinder problem but what harm will this create?

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[tallcanadian]

Boys, I'm kind of at a loss here. I don't see anywhere that water could be coming into. I guess my next step is to remove the water jacket. Just how hard can this be to remove. I don't see any corrosion around the bolts at all. I feel I need to keep going until I find some evidence of water leakage.

I've got two broken bolts to deal with now on the exhaust cover. I cannot budge those at all. Any suggestions, ideas, advice?? Anything at all.

I should change my name to Nervous Nelly. lol

 

[Chris1956]

You probably need to drill those broken bolts out and re-tap to correct size. Obviously, you need to be as accurate as possible. Also replace lower crankshaft seals.

Water leaks are usually confined to the exhaust baffle, inner water jacket cover and crankshaft seals. I would not remove cylinderhead water jacket, as you would need a crack in the block to leak from there.

 

[tallcanadian]

You probably need to drill those broken bolts out and re-tap to correct size. Obviously, you need to be as accurate as possible. Also replace lower crankshaft seals.

Water leaks are usually confined to the exhaust baffle, inner water jacket cover and crankshaft seals. I would not remove cylinderhead water jacket, as you would need a crack in the block to leak from there.

What about the cracks in the picture above? Is that any concern?

 

[Chris1956]

I cannot tell from the pictures it those are cracks or what they are. Maybe you can clean up the area more?

 

[tallcanadian]

They are cracks but looks like carbon has build up. Check the centre of this picture. You can see another well defined crack in the water jacket to the right of the opening where you can see the Pistons. What would make this crack in so many places? If this cracked so bad I guess it's possible that the block could be cracked. ? I'm away for Easter weekend but when I get I will check this area out more.

 

[merc850]

If you are a welder weld a nut onto the broken stub and while it cools turn the nut to unscrew it.

 

[tallcanadian]

If you are a welder weld a nut onto the broken stub and while it cools turn the nut to unscrew it.

That one I will try. My next mission looks like I will be removing the inner water jacket. I see cracks in it. I'm not sure how hard it will be to remove the bolts.

 

[Faztbullet]

Heat the crap out of those bolts as they are resiweld epoxied in place. When you replace it look carefully for any cracks around exhaust ports. DO NOT try to reuse the inner plate use ONLY a new one and use a gasket from Mercury. Mercury recommends resiweld epoxy sealer for the bolts. Put a straight edge on the block it has to be perfect. The original block has "diagonal" machine scratches" across the mounting surface. If these are worn off measure very carefully. If the block is warped the only thing you can do is replace the block or if minor, surface the block at the ports. If you do you will also have to surface the outer gasket surface for the 2 outer plates as well or the inner plate will interfere with the outer plate.

 

[tallcanadian]

I picked up a donor motor. I'm going to tear it down. Like a practice motor, before I rip mine apart.

 

[tallcanadian]

So I tore the donor motor down. It has a good baffle plate. The inner water jacket looks good as well but the design is a little different. It looks like the exhaust opening on the donor motor opens at the bottom of the plate. On mine, it opens at the third cylinder down. My question is can I swap out the plates or what is the major difference on the openings. I've included pics. The top pic is from the donor, a1975 850. The bottom pic is mine.