200 Johnson Water Tube (1996)

Srl700

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Does anyone have an idea how to replace the water tube on a 200 Johnson (1996). I'm quite sure it slides in from the top. I'm pretty deep into it now but having problems removing the exhaust housing. Any help would be greatly appreciated.
 

Chris1956

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There is nothing in my OEM service manual covering your issue. I did that work on a Merc, one time. There was nothing in the Merc service manual either. I had to discover the procedure, as I went.

On the Merc, the water tube was a friction fit in a rubber bushing, in the casting of the exhaust extension. I would think the Johnny would have something similar.
 

Texasmark

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Grasp it and pull down and see what happens. OMC was late in coming out with that lower casting design. I think it came about in '69 when they did their mid range looper change. I had a '72 125 which is what yours is in a different can of rattle paint after they prop rated from powerhead rated like mine, and it "smelled" of Merc. As Chris said, probably a friction fit. Why not. You have a slightly semi-rigid tube supported on both ends, why not just push it in. Besides common sense says that you couldn't get up at the power head end without removing the mid section to get a nut anyway and what designer in his right mind would do that?
 
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Srl700

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Thanks for your input and responses...as it turns out after finding a roadblock to every idea of a shortcut, I gave up on quick fix ideas and decided to start taking things apart. What I found is there is no shortcut to replace the water tube on a 1996 200 Johnson. I'm sure the same is true with other larger Johnson outboards of that era as well. I have the 20 inch drive shaft vs the 25 or 30". The 20" has a 1/2" water tube which is a copper tube straight cut on the bottom but flared on the top. The flare serves a purpose. The tube slides in from the top of the exhaust housing and rests on the flare with a rubber seal around it and therein lies the issue with taking any short cuts. On top of the exhaust housing is an adaptor plate. The adaptor plate is just a complex sandwich plate with water and exhaust channels that integrates the powerhead to the exhaust housing/mid section. So the powerhead sits atop the adaptor plate. The adaptor plate attaches to the powerhead and exhaust housing with bolts going in both directions. The adaptor plate cannot be removed from the exhaust housing without removing the powerhead. So in order to replace the water tube the powerhead must be removed BUT some of the bolts which hold the adaptor plate to the exhaust housing are underneath the steering mount brackets. So you have to completely remove the mid section from the boat but that's really easy because once the engine is removed, there are only 2 bolts on the top and 4 on the bottom which holds mid section to the steering coupling. Once the mid section is removed its just a matter of finding all the bolts from top and bottom (adaptor plate to exhaust housing) to separate everything. A quick note I started this process with the lower unit and all the cowlings already removed. I did this entire job on my dock, bought a $100 chain hoist to lift the power head off and not knowing really how to do it and also taking my time I probably had a little over 10 hours in the job. At least an hour and a half or 2 was spent on cleaning the old gaskets off. So when you get down to actually being able to remove the tube, the engine is hanging and the exhaust housing/mid section is completely removed and dissassembled. Sounds complicated but SERIOUSLY its really NOT difficult after seeing how it all comes apart. Just nuts and bolts. I could easily do it in HALF the time knowing how to do it now. Not counting my labor I have less than $200 invested. The local boat repair place quoted a guesstimate around 8 hrs labor @ $90/hr + parts. I figure I saved somewhere between $700-$800 on DIY and at least the 3 weeks I was told it would take to schedule in and out. I firmly believe those are minimum numbers. You will need all the gaskets/seals from the power head down. Hope this helps anyone who finds the same trouble. BTW this engine application is on a 21' Cajun if it matters about the steering arm mount.
 

Srl700

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....PS.... And YES what designer in his/her right mind would do such a thing!!!!!!
 

JoLin

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In 50 years ot tinkering I've never seen a boat, car, engine, drive, etc., etc., etc., designed/built by people... that didn't have at least one 'WTF were they thinking?' component.
 

Texasmark

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Well my last engine was a 2004 90 Merc. and they did do something about it. They finally put a bracket at the top of where the LU interfaces with the midsection that holds the pipe in place and makes the mating job easier. About time I said.
 
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