1989 90 Hp Johnson Block Question Pic Attached

trelos67

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Hi All,


Reading through a thread on here, and brings me to a question. My rig is at a marine mechanics at the moment, he phoned me Friday and showed me corrosion damage shown in the attached pic. My question is how bad is this, and how much life does this motor have left? I would appreciate your opinions be they good or bad.

Cheers
Craig from Australia
 

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Clyde Jones

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hard to tell from the picture, but is the corrosion almost into the cylinder wall? looks like its very close, but as long as the gasket can seal seems like it would hold.. what did the mechanic say about putting the heads back on? ... I am going through a similar issue
 

trelos67

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Hi Clyde,

Mechanic is sitting on the fence saying I might get a month out of it, might get longer. He showed me as he cant warrant it, which is fair enough. We pulled the heads to do the deflector hoses, and this is what he found. He thinks we might get enough bite on the gaskets to run it, was just wondering if others have had this happen and what was the life expectency of the motor?

Cheers
Craig
 

schuder

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I would like to check the compression of my 1959 35 hp super seahorse can I get a accurate measurement without the carb mounted on the motor?
 

boobie

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Yes.....And read the rules at the top of the forum and start your own post !!
 

Clyde Jones

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how much is it gonna cost to fix? If i were you i would almost just run it and see what happens.. cheaper than buying a new engine and if it works that's a plus too
 

emdsapmgr

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Looks like the head gasket seal ring surface on the top of the block is still ok. It appears continuously flat all around both cyls, including the one area you have circled. Corrosion next to the surface, but still-it looks like it will still seal with a new head gasket. Install your new deflectors and head gaskets, then do a compression check. Think I'd try to clean the water passages a little more. Looks like there is still a lot of whitish crust all around both cyls. That is narrowing the water flow passages slightly.
 

oldboat1

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When salt water running, I cleaned out water passages with a small screwdriver and a pick -- had the idea you had to physically get the deposits out, then flush. My tools were usually a a selection of small screwdrivers, avoiding any mating surfaces -- pulled off all covers to get at the passages. I would like to hear how shops handle it -- now up in fresh water country, so not a current issue, but curious. (Clyde's motor appears to me to have even more corrosion, but maybe not quite the damage -- think it could be scraped and flushed.)

On that damage shown, I'm pessimistic. I would think the corrosion at the face of the cylinder might make it a lost cause -- can imagine light picking at the spot would find more corroded metal. The shop says it might last for a while, and no reason to doubt that, but don't think I would want to use it that way. It might be time for a new block (JMO.)
 

trelos67

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Guys thanks for the feedback and your interest. No idea of the cost as yet, I am due to get her back either today or tomorrow and will give you an update. As we stand right now, the mechanic is going to put it back together and do a compression check and see where we end up. I went down there again yesterday, and the apprentice was cleaning the water passages with with a small pick and wire brush. They have picked a bit more at the corroded area, and no more metal has let go. Fingers crossed I might get the rest of the season with this damage, I am already on the hunt for a replacement block, and I think I will give it a go over winter. I am pretty handy on the tools, so if I take my time I cant see why it is not achievable at home over winter. Will let you guys know how we go when I get the boat back. Cheers
 

trelos67

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No Title

This is what came out of the block.
 

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Chinewalker

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If the corrosion to the casting is through to the sleeve, you're on borrowed time as the casting supports the sleeve. I've seen a few motors over the years where the casting has eroded and the sleeve then warps into that void. This is followed by compression loss in that area as the bore is no longer round.
 

racerone

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Those rubber pieces guide water around the block for proper cooling.-----New ones MUST be installed !-----If I was on a budget as far as good used blocks was concerned I would fix that block.------Machine away the bad material and shrink on a new sleeve about a 1/4" wide.----I see no problem with that block now and it may run for a long time. ----Note , many work to a different standard.
 
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oldboat1

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Hope you get some fun out of it yet. Maybe there is something to aid flushing -- products like Calgon or Borax over here (or whatever replaced them), something for dissolving calcium deposits -- and cheap enough to use for flushing.
 

trelos67

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I have been using a product called Salt Away for about 12 months. One might suspect this damage was done before I bought this rig.
 

oldboat1

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Probably right on the damage. Sounds like the shop will be pretty straight with you -- like to hear how it goes.

Best.
 

Clyde Jones

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yeah i used small screwdrivers, picks, wire brushes and pipe cleaner brushes.. seems like most of my corrosion is gone.
 

emdsapmgr

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Should run a lot cooler with most of the calcium/debris removed from the water jackets. Before you started all this work on the block, did you do a compression test on all 4 cyls?
 

trelos67

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Should run a lot cooler with most of the calcium/debris removed from the water jackets. Before you started all this work on the block, did you do a compression test on all 4 cyls?

Who me or Clyde? My compression was 130 across all 4, only had an overheat issue which prompted this head off excursion. She ran like a top and pulled like a train.
 
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