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MontreAl

Risers *and* manifolds?

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After getting over-temp alarms, (not overheating), I consulted my local Marinemax dealer who once knowing the year of my boat, immediately said manifold replacement was needed. Since this looks like a simple bolt off/bolt on procedure, I decided to tackle it myself.  The motor is a 2008 8.1 liter Mercruiser with closed circuit cooling.

First I pulled of the risers, (6-inch version), and was pleased to find blocked water inlets:  https://photos.app.goo.gl/av8dKMUyeHLAAufe7

Looking into the manifold water inlets, they look clear to me: https://photos.app.goo.gl/SBm3wmFaMVJrEtDU7

  https://photos.app.goo.gl/JpbVJwAtUGcpK1mg9

https://photos.app.goo.gl/gk5aWcS7R6Y66dyU6

https://photos.app.goo.gl/79dEDR8YtBdJJdPb6

So, have I found the problem, or do I need to dig deeper and remove the manifolds?  I am tempted to simply replace the risers and give it a go.

 

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20 minutes ago, MontreAl said:

After getting over-temp alarms, (not overheating), I consulted my local Marinemax dealer who once knowing the year of my boat, immediately said manifold replacement was needed. Since this looks like a simple bolt off/bolt on procedure, I decided to tackle it myself.  The motor is a 2008 8.1 liter Mercruiser with closed circuit cooling.

First I pulled of the risers, (6-inch version), and was pleased to find blocked water inlets:  https://photos.app.goo.gl/av8dKMUyeHLAAufe7

Looking into the manifold water inlets, they look clear to me: https://photos.app.goo.gl/SBm3wmFaMVJrEtDU7

  https://photos.app.goo.gl/JpbVJwAtUGcpK1mg9

https://photos.app.goo.gl/gk5aWcS7R6Y66dyU6

https://photos.app.goo.gl/79dEDR8YtBdJJdPb6

So, have I found the problem, or do I ned to dig deeper and remove the manifolds?  I am tempted to simply replace the risers and give it a go.

 

I'm doing mine this spring also and I wish I did it last year as it showed all the signs of needing replacement, but mine is a VP so obviously a little different, but I expect the blockage to be similar at the water jackets, even though they do get hot but not enough to not enough to not be able to touch them and hold them.  But man are those friggin things expensive.  Not sure about your Merc, but my lowest number (including the manifold) and I have the 6inch extension kit on the between the manifold and the riser/elbow (BTW, they should just pick a name and go with it because it confuses the crap out of everything when the risers are the same thing as the elbows.  My least expensive quote for the entire thing including the manifolds and gaskets and new bolts etc. was around $1,800 at Michigan Motors I believe, courtesy of @rjbergen who pointed me in that direction. 

I'm also in salt water for half the 9-10 years these original manifolds and risers have been on, so I have no problem changing them as I think they've done their job and then some.  And, since I do actually enjoy this kind of work, I'm actually looking forward to doing it.  If you want my opinion an can afford it, change it all including the manifolds.  You'll feel better and get better.

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I recommend pulling them and inspecting them yourself. If you see anything that concerns you, then replace them. If they look ok to you, then give a professional mechanic a couple bucks to look at them. It could save you from pulling them again in the near future to replace them. Given the damage that can occur due to those things, I don't mess around with my inexperienced eyes with those things.

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40 minutes ago, Chewey said:

I recommend pulling them and inspecting them yourself. If you see anything that concerns you, then replace them. If they look ok to you, then give a professional mechanic a couple bucks to look at them. It could save you from pulling them again in the near future to replace them. Given the damage that can occur due to those things, I don't mess around with my inexperienced eyes with those things.

I am not sure what can be visually inspected, aside from looking into the water inlets, which I have done.

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6 minutes ago, MontreAl said:

I am not sure what can be visually inspected, aside from looking into the water inlets, which I have done.

I wet sand blast the ID and use a bore scope. If you are friendly with a local machine shop they may let you use their sonic checker so you can read wall thickness, and finally a pressure test after sand blast.  I epoxy coat the outside.   W

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59 minutes ago, Wingnut said:

I wet sand blast the ID and use a bore scope. If you are friendly with a local machine shop they may let you use their sonic checker so you can read wall thickness, and finally a pressure test after sand blast.  I epoxy coat the outside.   W

I tried using my bore scope to check my risers last week.  Can't get in there cause they're jacketed.  Not sure about the manifolds tho.

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If they are older than 5-7 years go ahead and replace them as they've reached their life span.  Without checking the thickness of the walls and knowing if there is or isn't any hot spots inside of the manifold - why take the chance?  Visual inspection isn't good enough when it comes to manifolds.  If you do decide to change the manifolds out, let me know, I have some tips for you as I did my own a few months ago and I also have twin Mercs.

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On 10/14/2019 at 11:32 AM, Hatem said:

I'm doing mine this spring also and I wish I did it last year as it showed all the signs of needing replacement, but mine is a VP so obviously a little different, but I expect the blockage to be similar at the water jackets, even though they do get hot but not enough to not enough to not be able to touch them and hold them.  But man are those friggin things expensive.  Not sure about your Merc, but my lowest number (including the manifold) and I have the 6inch extension kit on the between the manifold and the riser/elbow (BTW, they should just pick a name and go with it because it confuses the crap out of everything when the risers are the same thing as the elbows.  My least expensive quote for the entire thing including the manifolds and gaskets and new bolts etc. was around $1,800 at Michigan Motors I believe, courtesy of @rjbergen who pointed me in that direction. 

I'm also in salt water for half the 9-10 years these original manifolds and risers have been on, so I have no problem changing them as I think they've done their job and then some.  And, since I do actually enjoy this kind of work, I'm actually looking forward to doing it.  If you want my opinion an can afford it, change it all including the manifolds.  You'll feel better and get better.

Try Barr risers and manifolds, I believe they mae them for VP.

Years ago I used them and saved a bunch.

You can also try GLM, many here have had success with them.

I had a riser fail after two years so not my choice.

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Don't order from GLM.  They sent me the wrong Manifolds/Risers and wouldn't cover the cost to ship them back.  I had to pay $630.00 to ship them back to them.  Their Customer Service is garbage even though their prices are good.

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Did you check Cecil Marine pricing?  Their pricing is pretty competitive.  I will never, ever spend another dollar with Michigan Motorz.  I believe somewhere on one of these threads about replacing steering actuators, I told my story about getting screwed by Michigan Motorz on a steering actuator that had bad seals from the get-go (I suspect old stock sitting on a shelf) that they would not make good on.  I got hosed out of about $600 bucks and they humored me for a little bit with emails and then stopped communicating altogether.  Proceed at your own risk but they'll never get another (wasted) dollar from me.

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Follow up to my riser replacement:

After visually inspecting risers and manifolds, I decided to replace risers only. They were seriously clogged and the manifolds appeared to be clear. With new risers installed I test ran the JAH Love yesterday.  After several high speed passes along a section of the ICW near my homeport, I am pleased to report a successful result.  No overtime alarms.  I suspect this may be a temporary fix - as the OEM manifolds age they may also get corroded and eventually restrict cooling water flow. For now, all is well.

Thanks for all the advice fellow boaters.

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