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Roady68

Preemptive Replacement of Manifolds and Risers

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So we enjoyed our first year with our Sig 300 immensely.  Spring is still four months away, but I am starting to create the pile of parts and tools needed to get to work as soon as spring springs.  One of the issues that is causing me some concern are the manifolds and risers.  The boat was used in salt water prior to us purchasing it.  Previous owner could not produce receipt for last change of manifolds and risers though they looked new (paint was shinier than engine paint) on the outside.  Since something going wrong here can lead to catastrophic damage in the engine, I am thinking about swapping them out before we splash it this summer.  The boat had showed no signs of overheating (well, except when bearing went on water pump).  I assume they cannot be replaced once boat is floating in the water.  I did want to try to get some thermal pictures of manifolds (a coworker has a FLiR attachment to his camera), but would need the boat to be in the water under load to get meaningful data.  Its a pain to get the Marina to haul out.  I'd rather put the haul out charges to new parts. Parts are not cheap when doing two engines, but cheaper than replacing whole engine.  I am guessing $1200 or so for parts.  Is there a difference between Mercruiser and Sierra parts in this application?  

So two questions.  First, does this make sense?  Is there an other option such as boroscope inspection?  Second, or is this third, how difficult of a job is this?  It can be done with engines still in the boat I assume.  I am having Marina put boat on work rack when I get ready to splash it.  They'll leave it there for 7 business days with not charge which is cool.  I'll take a couple of days off work to do this.   I've rebuilt many engines including my 472cu in Hemi, so not worried about the mechanical aspect.  It is the boat specific items that I want to watch for (such as rusty bolts, special gaskets, special tools, etc).  

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Since you are not seeing any signs of them being bad it has to go under the category of preventive maintenance. Once you start removing them you will know if it was close to being needed. It will be obvious if they were recently replaced or not. 

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Only way to know if you need them is to take them off and look.  If you youtube it there is ways to test them.  Otherwise you could just take off quickly inspect and replace with new seals.  If the boat was in salt water most will say they need them every 5 years or so.  Guess it will also depend if the boat was taken out every time and flushed or sat in the water.

 

As far as parts I did mine on my Volvo last year.  I opted for GLM, for the set it was around 550 bucks or so on ebay, ebay has good deals. Set included manifolds, riser,bolts and gaskets.  Sierra or GLM for the set were about 5-600,  Volvo and merc sets were 800-1000.  As far as quality I matched up the GLM to the Volvo ones that came stock and they were identical and seemed to be of equal quality.  Since Volvo doesn't make their own marine manifolds I assume, wouldn't surprise me if they didn't come off the same line somewhere.  With that said seals are important don't use the paper ones, use the ones that look like foil and don't use gasket seal.  A lot of guys buy off brand manifolds and buy OEM gaskets.  Also your kit should come with new manifold bolts,  save your self the headache.  take two old bolts and cut the heads off.  when installing new manifold by hand or with vie grips half tighten the cut off bolts into the holes on the end., slide gasket on and manifold on, and  Insert new bolts in the middle, take out cut off bolts insert new and torque them all down evenly.  really not a bad job.  maybe an hour or so per engine.  youll have to disconnect a few things,  probably shouldn't be done in the water, and I don't see why the engines should be pulled.  Took me an hour or so to just put on one side until I figured out the bolt trick, then the other took 10 mins.  Could use would dowels too, but the bolt method worked great.

if your going to do manifolds do the risers as well.

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Every amount of water blocking minerals will be different. Because of saltiness of the water. POLLUTION of the water.  If engines have FACTORY HOT thermostats.  Engines have old enough STICKING CLOSED thermostats............Do we have enough reasons to definitely pull them off & running them in a RADIATOR SHOP clean out tank ? Then tapping them with a hammer  to dent, cave in, knock a hole into it. 

Good mechanics know all these basics to look for. & how to check them out for you.

5 years in Florida docks all year ?   5 years in Mass ?  Pulled out each winter months.

I would pull them to check GASKETS for corrosion eating up metal under the gaskets.  New gaskets.

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7 hours ago, Phillbo said:

Since you are not seeing any signs of them being bad it has to go under the category of preventive maintenance. Once you start removing them you will know if it was close to being needed. It will be obvious if they were recently replaced or not. 

 

6 hours ago, soldier4402 said:

Only way to know if you need them is to take them off and look.  If you youtube it there is ways to test them.  Otherwise you could just take off quickly inspect and replace with new seals.  If the boat was in salt water most will say they need them every 5 years or so.  Guess it will also depend if the boat was taken out every time and flushed or sat in the water.

 

As far as parts I did mine on my Volvo last year.  I opted for GLM, for the set it was around 550 bucks or so on ebay, ebay has good deals. Set included manifolds, riser,bolts and gaskets.  Sierra or GLM for the set were about 5-600,  Volvo and merc sets were 800-1000.  As far as quality I matched up the GLM to the Volvo ones that came stock and they were identical and seemed to be of equal quality.  Since Volvo doesn't make their own marine manifolds I assume, wouldn't surprise me if they didn't come off the same line somewhere.  With that said seals are important don't use the paper ones, use the ones that look like foil and don't use gasket seal.  A lot of guys buy off brand manifolds and buy OEM gaskets.  Also your kit should come with new manifold bolts,  save your self the headache.  take two old bolts and cut the heads off.  when installing new manifold by hand or with vie grips half tighten the cut off bolts into the holes on the end., slide gasket on and manifold on, and  Insert new bolts in the middle, take out cut off bolts insert new and torque them all down evenly.  really not a bad job.  maybe an hour or so per engine.  youll have to disconnect a few things,  probably shouldn't be done in the water, and I don't see why the engines should be pulled.  Took me an hour or so to just put on one side until I figured out the bolt trick, then the other took 10 mins.  Could use would dowels too, but the bolt method worked great.

if your going to do manifolds do the risers as well.

I Agree with both these guys, with not much more to add, except that EBay scares me, I found Lighthouse Marine had great prices on manafolds, especially OEM!

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A friend at our marina has a 300, great boat, has been restored to look like new, amazing.

I can't offer advice on how to test or diagnose, but if you or someone open them up and just have it replaced, you wont worry about it further.

Same as impellers, etc.

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Thanks all.  Only issue I have is that once the boat is on a work rack, the timer starts ticking and I have to get a lot of work done in 7 days.  They are usually good if you need another day or two, but its a queue for everyone else who also needs to do work.  So I don't want to hog one of the work racks and keep someone else from getting on the water.    I am afraid if I pull it, and want to replace it, I will be at mercy of availability and shipping.  Hence the desire to purchase parts now.  Other option is that I opt for a very early splash.  Usually folks don't get antsy to splash until Memorial Day weekend so there may nod be a demand for work racks.  I'll have to ask them when I go and make my slip deposit.

 

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On ‎1‎/‎19‎/‎2018 at 5:54 PM, Duane2135 said:

 

I Agree with both these guys, with not much more to add, except that EBay scares me, I found Lighthouse Marine had great prices on manafolds, especially OEM!

ebay has come a long way,  at this point its no different than amazon in terms of its protections and guarantees.

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Volvo manifolds are made by Barr.

Great tip on the bolts, it will save you a lot of time and skinned knuckles

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Not knowing how difficult it really is to pull your boat out of the water, couldn't you plan to skd something mid season? This would give you an opportunity to IR your engines before you tear them apart. If they look good, defer it until next year. Is your shop usually quiet during mid season or very busy?

 

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Tough to get everything the way you want it.  Can you buy the stuff ?  Have it all ready. Pull apart. Looks good ship back what you will not need. .....Tell the place you want to buy from. SEPERATE SET OF GASKETS in case all metal looks great. No need to open new parts up.

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12 hours ago, cyclops2 said:

Tough to get everything the way you want it.  Can you buy the stuff ?  Have it all ready. Pull apart. Looks good ship back what you will not need. .....Tell the place you want to buy from. SEPERATE SET OF GASKETS in case all metal looks great. No need to open new parts up.

This is an option.  Or just keep them on the shelf as I am sure they will need replacing at some point.  We don't plan on changing boats in the next few years, so they will most likely get used on this one.   SST has a good idea too. 

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Fresh water only ?  DO NOT BUY & store money on a shelf. Fresh water rusts a lot slower each year. What year are the boat & engines ? Hours on motors ?

A FULL GASKET set is what I would do when you have it out of the water. & on stands tilted up at the bow. Standing water freezes in bilge pumps & slimes if stagnant.

No rush. Get a place that will take UNOPENED boxes back. You eat the shipping charges & may be about $ 50 for restocking fee.

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1 hour ago, cyclops2 said:

Fresh water only ?  DO NOT BUY & store money on a shelf. Fresh water rusts a lot slower each year. What year are the boat & engines ? Hours on motors ?

A FULL GASKET set is what I would do when you have it out of the water. & on stands tilted up at the bow. Standing water freezes in bilge pumps & slimes if stagnant.

No rush. Get a place that will take UNOPENED boxes back. You eat the shipping charges & may be about $ 50 for restocking fee.

boat was used prior in salt with know known replacement.  Best case in salt you can go 10.  Freshwater boat can probably go their whole lives with the original set.  At minimum the OP would be wise to crack em and replace seals.  Not like these parts spike in pricing so I don't really see spending money and putting parts on the shelf either.  If it were me, Id probably suck up the investment now and replace them, 1000 bucks or so, and a half day of work that worry is gone for ever.

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Not to hijack this thread, but I'm curious as to how many salt hours the knowledgable folks on this forum consider the point where the 'salt timing' applies to the manifolds and risers?  I bought my boat at 4 years old with 38 hours on it, as a Florida boat (flushed and stored in a dry rack every time), but the rest of its life will be solely fresh water.  Is 38 hours enough time in the salt to be concerned, or can I go with freshwater lifespan estimates at this point?

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I bought a salt-water boat with 60 hrs and it's been in fresh water ever since.  Same as you, boat dry stored and flushed after every use.  I've never had any issues with the manifolds or risers (or anything other than WP impeller) and it's going on 14 years and 600 hrs.

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1 hour ago, sburke91 said:

Not to hijack this thread, but I'm curious as to how many salt hours the knowledgable folks on this forum consider the point where the 'salt timing' applies to the manifolds and risers?  I bought my boat at 4 years old with 38 hours on it, as a Florida boat (flushed and stored in a dry rack every time), but the rest of its life will be solely fresh water.  Is 38 hours enough time in the salt to be concerned, or can I go with freshwater lifespan estimates at this point?

probably not much because you had low hours and racked and flushed everytime. 

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IMG_20161110_171655.jpg.dff9b4a2b9235f4a279c4c6c75bd12a2.jpgJust want to share my experience in diagnosing and replacing my exhaust manifolds and risers on a 2010 270 Sig, 350 Mag bravo 3. I bought the boat with 210 hrs, 3rd owner. The boat has been ran in salt water since new. 2nd owner really took care of the boat and always ran salt terminator through the engine after every use. Not too sure first owner treated the boat the same.  I followed the practice after I bought it of using salt terminator after every use. I had put about 30 hrs on engine prior to an overtemp condition I had while cruising in the gulf coast. My troubleshooting consisted of removing thermostat housing, raw pump and one of the risers. The thermostat housing was a bit corroded but serviceable and so was the pump, the risers on the other hand was corroded to the point where one of the water jackets was 85 percent plugged with rusted metal. I decided to replace both manifolds, elbows and risers plus thermostat housing. I used original MERCRUISER OEM parts and paid a bit more than I probably should have. There are other alternative parts out there that are high quality and are rated same or even higher than the OEM parts, Sierra and Barr are two highly rated alt parts. I'm just a bit OCD so decided on OEM parts. During my research and calling Chapparral for advice I found out that the risers and manifolds are part of PMI checks and should be replaced every 400-500 hrs of use specially in salt water conditions. I guess it all truly depends on use and how the engines are flushed after use. As I mentioned earlier, I use salt terminator in hopes to extend the life of the new manifolds and risers I installed. After repair, the boat runs like a champ at a steady temp of 156 degrees. Ran boat 2 weeks ago for 2 hours at  30 mph and the hottest it got was 160. I confirmed temp with a laser temp gun and it registered 159 so it was pretty close. The R&R of the risers and manifolds is pretty easy depending on engine access. I only have one engine and I'm small framed so it was easy for me. As someone mentioned this thread, there are many videos on you tube explaining the process. I wish I would have taped my install to share. I will definitely do it next time I do some PMI or upgrades to the boat. Sorry for long post. Just wanted to share my experience. 

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Sorry to bump an old thread, but I see a ton of advice on replacing manifolds and risers, but nothing about the elbows themselves.  Do they "wear" at the same rate as the risers and manifolds?  Should they typically be changed at the same time?

And what about pulling elbows, risers, and manifolds while in the water?  Seems to me the risers keep everything above water line so should be no problem.  Am I mistaken?

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Uncanny timing.  I didn't have a chance to do the manifold work as I damaged my lower outdrive case on the starboard engine.  That pretty much ate up my time and budget.  I am starting to compile a list of things to do for 2019 season so this is back.  We had no cooling issues last year, so I think I am probably OK, but curiosity is getting to me.

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28 minutes ago, Roady68 said:

Uncanny timing.  I didn't have a chance to do the manifold work as I damaged my lower outdrive case on the starboard engine.  That pretty much ate up my time and budget.  I am starting to compile a list of things to do for 2019 season so this is back.  We had no cooling issues last year, so I think I am probably OK, but curiosity is getting to me.

Yeah, curiosity is getting to me as well.  I don't show any cooling issues, but the boat is now 11 years old.  And although 99.9% of the hours are freshwater, I do like to take it to Florida once or twice per year.  So far, it's only seen saltwater about 10 days total.  I flush after each week of saltwater usage (when pulling out and heading home).  Anyway, I'd like to inspect it and change the gaskets, but wasn't sure 1) if I needed to check the elbows (might as well, I guess) and 2) whether I can do it in the water or not.

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Do not feel too bad. 

2 basic types of maintenance people. Change a little too soon or in doubt.

Change it when there is a sign a part is just starting to really fail.

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2 hours ago, TexasPilot71 said:

Sorry to bump an old thread, but I see a ton of advice on replacing manifolds and risers, but nothing about the elbows themselves.  Do they "wear" at the same rate as the risers and manifolds?  Should they typically be changed at the same time?

And what about pulling elbows, risers, and manifolds while in the water?  Seems to me the risers keep everything above water line so should be no problem.  Am I mistaken?

Recommend replacing all at the same time. Since it’s all disassembled, it prevents additional cost and downtime. No, they don’t tend to “wear” nearly as fast but you don’t know until into it. 

The work can be performed on the water depending on how “rough” the slip is.

A bit of personal preference follows. I’m not a fan of the boat moving while working. I find by naturally narrowing my vision when concentrating and focusing below chest height I get a bit of motion sickness. Kind of like reading in the car, particularly the backseat, for me. Just personal preference. 

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20 minutes ago, Curt said:

Recommend replacing all at the same time. Since it’s all disassembled, it prevents additional cost and downtime. No, they don’t tend to “wear” nearly as fast but you don’t know until into it. 

The work can be performed on the water depending on how “rough” the slip is.

A bit of personal preference follows. I’m not a fan of the boat moving while working. I find by naturally narrowing my vision when concentrating and focusing below chest height I get a bit of motion sickness. Kind of like reading in the car, particularly the backseat, for me. Just personal preference. 

Good stuff.  Thanks, Curt.  Our slip is very well protected and I work in there all the time.  Honestly, I have never even noticed motion while in there.  Never been motion sick either (blessed for sure!)  Wish there was a way to use a borescope to get in and check the status.

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15 minutes ago, TexasPilot71 said:

Wish there was a way to use a borescope to get in and check the status.

Totally agree. Would add less than about $20 to the OE build to include a pair of ports and plugs on each side. Just like scoping a turbine, just dirtier.

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