What started out as a good weekend quickly went down hill. Picked up all the parts to re-install the refurbed heat exchanger with new hoses and got it all done yesterday. I noticed a broken clamp on the raw water input from anti-siphon and replaced it no problem. The I noticed a pin hole in the hose from riser to muffler and new I had to replace it. So I did lots of reading here last night and decided to use a Ventus hose based on a post from Roc. So I cut or the old hose and when I went to remove it from the exhaust riser it just broke off in my hand. It was corrorded to no end. So I took the riser off the engine and now have more questions on what to order:
1. Do I need to send the old one to Catalina Direct to get the new one?
2. Do I need to remove exhaust flange from engine and replace it?
3. In one post it said to use something else with the flange gasket, cannot find the post again.
4. Any tricks to re-installing this.
5. I know I need to wrap the exhaust. Do you recommend the jacket from CD or use regular much let / header wrap.
6. I am ordering all new stuff so I do not have to do this again, any other suggestion to look for?
I could occasionally smell a little exhaust underway and knew I had a leak somewhere but could not find it, so maybe all this will fix other little issues.
Thanks in advance.
Brian Yates
Hakuna Matata
2000 MKII # 1517
M-35B
Brian,
Yes CD wants the old one to have the new fabricated to be an exact fit. You might talk directly to CTY also. I know a C-30-er who ordered a CD riser and was out of commission for months -- wasn't happy about CD's customer service. Dunno if it was an anomaly, CD seems to be hit or miss from what hear.
An alternative is to fab the riser yourself (or otherwise locally) from schedule 80 black pipe or stainless nipples and elbows. Never ever use galvanized pipe due to off gassing.
I bought my exhaust wrap and stainless clamps from autozone -- haven't installed yet. As I will probably replace mine with the Westerbeke water -cooled riser upgrade, no need for a wrap then.
I while back I put an article on techwiki about refurb of an aqualift muffler. While you have everything off I would make sure it is well reinforced -- better now than when it starts leaking later. MIne leaked 2x - and then I deep-sixed it.
You probably won't get the riser off the flange -- might be easier to just replace all. You may need new flange studs -- can't tell until you see how it all comes apart.
Where are you located BTW?
Good luck!
Ken
Ken,
Thanks for the data. We are in San Diego. This is a killer. The boat has only been back in commission for a couple of months after it got hit and had to replace port stern rail. But glad it happened now rather than when on trip this summer.
Brian
Ken,
What is the water cooled upgrade? Where can I find write up. Sounds interesting.
Quote from: bayates on May 01, 2016, 09:16:56 PM
Ken,
What is the water cooled upgrade? Where can I find write up. Sounds interesting.
Brian I mentioned it on the forum a while back. See attached. These are C30s (have done 2 Universals and 2 Beta 20 repowers this way) -- notice the "reverse" entry to the side in/top out waterlift - I worked out that design with Centek engineering to eliminate any chance of backflow to the exhaust valves while heeled. It works swimmingly with the layout of the C30 engine compartment -- I can't say about the 34 - I owned one for a week (chartered in FL) but don't recall the engine compartment layout/particulars.
The cooling water is from the vented loop and is injected into the exhaust gas at the end of the riser, carried to the waterlift so all runs cool. Slick setup. Chuck's beta was standard hose, the other 3 are silicone hose. Fittings are all Centek fiberglass. The last has no reverse entry - Centek doesn't recommend that way but that one wasn't my design.
kk
Water-cooled riser pic
Brian
BTW, Brad's is on an XPB, so the exhaust manifold is the same as your 35B (I forgot you have that) So ignore what I said about the flange, studs, etc - I was talking M25/XP. The 35B has a different type exhaust -- a doughnut gasket and clamp ring -- like off an auto manifold -- not studs. Actually easier than the studded flange on the M25/XPs.
There's a similar riser to below that fits your type exhaust manifold, rather than the pipe nipple off the threaded flange.
kk
Brian
PS, you'll probably find the exhaust manifold side pitted and really worn -- Brad's was. He cleaned it up as well as he could and used hi temp RTV when installing the doughnut.
kk
When I visited the factory in March to pick up my new rudder there were exhaust riser's on the parts shelf. When mine failed a couple years ago they had a new one in the mail the next day. I would try the factory. IIRC they require pictures and measurements, but not sending the old parts to them.
Brian : Be careful with the advice that you get because you have a M35BC engine.
Your exhaust riser attaches with a clamp fitting and there's not that much space above that flange attachment because of the cockpit floor. :think
A few thoughts
When I bought an exhaust riser for my engine last year from CD they did NOT require the old one. I prepared a Tech Note on it: http://www.c34.org/mainsheet/html/2016/Muffler%20&%20Exhaust%20Riser%20Replacement.html
This is for a Mark I.
Lots of misinformation and misdirection in these replies. Sometime people try to hep too much. :D
Read the Tech Note if you're a C34IA member. If you read it, you'll pick up some answers to your original questions. Then you can come back and be more specific.
Quote from: Stu Jackson on May 02, 2016, 04:59:05 PM
When I bought an exhaust riser for my engine last year from CD they did NOT require the old one. I prepared a Tech Note on it: http://www.c34.org/mainsheet/html/2016/Muffler%20&%20Exhaust%20Riser%20Replacement.html
Stu,
Did CD change its policy? Direct from CD:
<<
Due to the subtle differences in length, shape and angles you must send your old riser to achieve a proper fit. >>
My experience is that CD won't guarantee a fit w/o having the old riser. It there's any issue, you've bought a custom part that's not returnable. Possibly that's no longer the policy...? But that's the experience we've had for replacing the M25/XP riser on the C30.
Regarding 'lots of misinformation and misdirection," can you be specific? Examples of each?
Cheers,
ken.
http://www.catalinadirect.com/index.cfm/product/1889/exhaust-riser-assembly-c-34.cfm
It does say: "Please see the additional images below for dimensional references. If none of the various risers we offer match your dimensions, you will need to send us your old riser to match."
This is for the Mark I riser. Nowhere does it say you have to send the old one in if yours matches their offerings. I didn't. That "policy" was from Catalina Yachts, and back in 2003, for my first riser replacement, I spoke to Robert Butler and faxed him my measurements, no need to send the old one it. If you're a wise customer it shouldn't be required. I did my second replacement last year in the link I provided in my earlier post.
Please note AGAIN, the link is for the Mark I riser. I didn't look for a Mark II riser. It has a different shape.
Quote from: Stu Jackson on May 03, 2016, 09:31:28 AM
http://www.catalinadirect.com/index.cfm/product/1889/exhaust-riser-assembly-c-34.cfm
It does say: "Please see the additional images below for dimensional references. If none of the various risers we offer match your dimensions, you will need to send us your old riser to match."
This is for the Mark I riser. Nowhere does it say you have to send the old one in if yours matches their offerings. I didn't. That "policy" was from Catalina Yachts, and back in 2003, for my first riser replacement, I spoke to Robert Butler and faxed him my measurements, no need to send the old one it. If you're a wise customer it shouldn't be required. I did my second replacement last year in the link I provided in my earlier post.
Please note AGAIN, the link is for the Mark I riser. I didn't look for a Mark II riser. It has a different shape.
Stu,
I'm not making this up, and besides I wouldn't know what CTY's policy is. The statement is on the CD page (statement #7) for the M-35B riser (the engine in question -- the page you linked to isn't for the B-series engines. Also there are C30/M25-ers who had to send CD their riser. I'm not saying it's the same product as for any 34, simply that what's on the CD site that I copied/pasted for the B riser, is consistent with bretherns' experiences. Maybe the 34 Mk 1 riser is so 'Universal" (bad pun) that CD doesn't need to see it. Dunno.
Was that the only misinformation/misdirection so that we can push complete info out there to the vapor.
Cheers,
Ken
All,
Stu is correct. I talked to Kent at CD and they no longer require the old one to be sent in. We are lucky as they were due to receive some Tuesday at CD. Kent felt 2 days to assemble and then ship. I ordered all the parts from them except the mom-hump hose which I am using Vetus hose to replace the old hard sided hose for potential future issues. I am traveling through Sunday do replacement is s heckled for the 14th. I will take lots of pictures to share findings and end result.
I appreciate all the help here as it definitely gives you direction and visibility to issues.
Let's hope it goes close to plan. Nothing ever goes perfect.
Brian
Brian,
I emailed CD last night w/ a suggestion that they consider updating the webpage that says 'send us your old riser,' saying that I understood that it no longer applied to at least the C34, B-series riser.
The reply was no 'talk to sales because we may need your old riser.' Mercy me. Which further reinforces my JTSO that "customer service" at CD oftentimes maintains its noggin deeply inserted into its butt end.
kk
Ken,
I only deal with one person there and he has been awesome. He is a long time Cstalina employee now with CD has great knowledge and communicates well on issues and updates. Between the stern rail replacement and the riser no issues.
I know that Catalinas are production boats and there will be slight difference but I am a product person and design and ship stuff yet I am amazed at how little control over consistency there was at manufacturer. Fujitsu's customers would kill me if I did that and are goods cost significantly less for the product.
Brian
I did NOT send CD my old riser, it was NOT requested. I used the picture with dimensions from their website to verify it was the same as the unit I removed (30 yr old black pipe). I replaced all components from the manifold back (did this in Feb/Mar 2016); exhaust riser, hump hose, water lift muffler & exhaust hose. The information on this forum gave me more assistance than I can say, I purchased all items from CD except the exhaust hose, would have ordered that as well but my experience with their promised delivery date gave me pause. When I ordered the exhaust riser from CD & they told me I had to also purchase the exhaust riser heat cover. My only issue with the whole process was CD said it would ship the following day and told me delivery would take 5 working days. I made arrangements for a mechanic to be on board the following weekend. Without going into boring details, the items shipped one week later than promised, it was explained the delay was because the riser cpieces were in stock but had to be assembled. I am happy to deal with CD but make sure you include a delay factor into your schedule for any items that may need to be assembled.
I can confirm that you DO NOT send in your old riser to Catalina Direct. I have been told that Garhauer makes these risers for both Catalina Yachts and Catalina Direct and that the delivery quickness is dependent upon if it is in stock or if it needs to be built. Mine was delivered from Sacramento to Santa Clara in three days. Here is a comparison photo of the two side by side. The photo is a little distorted and they are the same dimension-ally. The new one is electro plated to keep the welds from rusting. I polished off the area around the injection nipple on the old one and found these two nasty surprises. The old one had a little rusting around the nipple and the factory insulation completely covered the cracks. Inside the riser there was "coking" in the area of the cracks and I could not clean well enough to see how extensive the cracks were on the inside.
I do have one question: How do I wrap the seizing wire around the manifold clamp?
This is an older thread but situation is similar. My water injection elbow failed and I am looking to replace the system. I have a 1992 M25XP, around 1700 hours.
I requested a quote from catalina yachts and I was underwhelmed at the response:
ello Mr. Gendreau,
"See photo attached. The C34 riser and 90O elbow at left in photo costs $265 unwrapped and $350 wrapped in wire mesh, fiberglass padding and thermal tape. The hump hose sells for $42.00. The flange, gasket, studs and nuts are engine parts. We do not sell them. You can purchase them from a Universal/Westerbeke dealer.
The thread size on our risers and 90O elbows are 1-1/2" NPT. It is possible your flange or replacement takes 1-1/4" NPT threads. In that case you would need a reducer. We don't sell those. They are a standard pipe fitting that you can get from a plumbing supply store if not a Home Depot or Lowes."
The picture attached to the email showed what looked like a galvanized street elbow from the riser to the engine flange. Their suggestion that I buy a 1 1/2 to 1 /14 reducer at Home Depot or Lowes seems to confirm it.
After all the negative articles on this board about using galvanized pipe for the riser, I was very surprised to see Catalina Yachts recommend this.
I was also bothered that they don't offer a riser that has the correct size pipe for M25XP engine flanges (1 1/4 inch). I will be speaking to them tomorrow about both issues.
>>Question - have others purchased risers from CY that included galvanized elbows? And were you able to buy the riser to fit a 1 1/4 flange without resorting to adapters from Home Depot.
Comparing what CY offers for risers to Catalina Direct- CD shows a photo including dimensions of a stainless riser that matches mine , except that the nipple that connects the elbow to the flange is 6 inches long compared to the close nipple on my present riser. I would not want to use the 6 inch nipple as it would position the riser too close to the engine compartment aft wall.
>>Question - have others had to have CD modify their standard riser to use a shorter nipple?
Quote from: Roland Gendreau on June 12, 2017, 06:41:40 PM
This is an older thread but situation is similar. My water injection elbow failed and I am looking to replace the system. I have a 1992 M25XP, around 1700 hours. >>>>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
>>Question - have others had to have CD modify their standard riser to use a shorter nipple?
No modificajtioin required for me, M25 Mark I, should be exactly the same dimensions.
See Tech Notes Online
http://c34.org/muffler-exhaust-riser-replacement-2015/ (http://c34.org/muffler-exhaust-riser-replacement-2015/)
Photo 4 shows what appears to be that 6 inch nipple. No install problems for me, in fact, a shorter one might NOT work, 'cuz it would bring it too far forward.
Roland,
The problem is very current -- I just was going through this with a C30 customer with an XP.
The problem is that, at some point, the supplier made two risers -- one with the 1-1/2" threads, and 1-1/4" threads to fit the proper 1-1/4" flange using an 1-1/4" stainless elbow. Unfortunately, Catalina has none of those left.
CD has the correct riser (at least for the XP in a C-30) but won't well he riser w/o the insulation, so the customer wouldn't buy it. Instead he's having his stainless fabricator make a complete stainless riser and flange attached for $400.
One option I gave him was to use a 1-1/2" Westerbeke flange with the 1-1/2" threaded riser. But I don't know if that is in stock (it costs more than the 1-1/4" flange.)
I spoke to CTY about the 1-1/4" vs 1-1/2" issue last week, to no avail. CTY said "try CD."
Please post the pictures of yours and the longer nipple from CD and what you got from CTY... so i can see what you have to work with.
it could be that you simply need to order a stainless close nipple (readily available.)
I believe the reason that they use the 1-1/2" threads is that the XPB engine uses a flange that is 1-1/2. not 1-1/4".
kk
Ken
Three photos below:
My existing riser, the Catalina Direct riser and the Catalina Yachts riser.
The CY riser looks it it uses a galvanized pipe elbow (to be confirmed).
ROLAND,
No it's a schedule 40 stainless elbow. 1- 1/2.
As I said, last week I've been all through this with CTY and CD.
What CTY had proposed was to supply a galvanized reducing coupling. The problem with that on the situation I had, was that it pushed The whole unit too far from the flange.
The owner could rotate the riser forward to compensate, but that would have put the injection elbow off-line of the muffler inlet.
He needed a close nipple and adding the reducer, which I think measured 4 inches threw it out of alignment.
I can't see the nipple. Is yours a close nipple or longer? Are the dimensions exactly the same as CD shows on its side?
I take back what I said last night. I didn't speak with Catalina about it-we emailed. I spoke with garhauer about it, who has made some of the risers before. They are not interested in messing with this.
CD had the correct riser, but will not sell it without the insulation and the owner wouldn't pay what they charge for that. So, he's having his fabricated. 400 total job as far as I know. Maybe his guy would be interested in making yours?
Or just use CD with a close nipple if that's what you need.
To close out this discussion, I was able to find an additional riser on the CD site for the M25XP, with the close nipple.
https://www.catalinadirect.com/index.cfm/product/2588/exhaust-riser-c-30-c-36-w-m-25xp-or-m-35.cfm (https://www.catalinadirect.com/index.cfm/product/2588/exhaust-riser-c-30-c-36-w-m-25xp-or-m-35.cfm)
I just placed the order, and hope they don't hold it up because I did not order the way overpriced thermal insulation kit.
Well as I said, owner was told "no" in no uncertain terms, He even offered to give CD a letter absolving them of any liability on not supplying the baby blanket.
If that doesn't work out for you, my alternate was to get the CTY riser and use a stainless reducing reducing street elbow.
OR, easy enough to have a shop rethread the 1-1/4" NPT flange to 1-1/2" NPT.
OR, use the 1-1/2" NPT flange.
Ken
Quote from: KWKloeber on June 13, 2017, 03:14:53 PM
Well as I said, owner was told "no" in no uncertain terms, >>>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>>>>>>>>>>
So was I. Mentioned in the link to my tech notes article.
Good luck.
CD called me after I placed the order for the riser to advise me that the insulation wrap was required and they would not ship me the riser without it. They wouldn't budge so I canceled the order.
I then ordered the riser and hump hose from CY, and told them to not provide the 1 1/2" street elbow. Since I could not find a 1 1/2" x 1 !/4" SS street elbow on Amazon. I ordered a 1 1/2" ss elbow, a 1 1/2" x 1 1/4" SS bushing and a 1 1/4" close SS nipple from Amazon, all for about $25.
All the parts should be delivered in about a week. I'll advise results.
Roland the anwser my "stainless guy" had was to simply fab a stainless reducing 90 street ell
Would take about 10 minutes.
It's no my bag so I may have some details wrong, nut basically he'd take a socket weld elbow and stick an 1-1/2 fm tread hub on one side and a 1-1/4' male thread on the other. And he'd make the distances match a standard schedule 40 street ell so that the riser would match up with position of the muffler inlet.
The other way to do it, is use a heavy wall (sch 80 or class 3000) 1-1/4" 90 ell, drill out/enlarge one side and retap to 1-1/2" female, and use a close nipple on the other side.
Hoe that the bushing doesn't add too much distance.
McMaster-Carr is a good source for a lot more oddball pipe fittings (and just about everything else in the world) than what you can find on amazon.
ken
With the riser from Catalina yachts, I used a 1 1/2 " elbow, and a 1 1/2 bushing and close nipple to connect to the flange. Although slightly longer, there were no clearance issues installing it on the boat.
Catalina offered to wrap the riser with insulation for aout $90. That option was estimated to add about a week to the delivery cycle, which I did not want to happen. When I discussed it with CY, they said they would include enough wrap for me to do it myself. They did not charge anything for this. The amount of wrap provided allowed me to wrap it at least three times.
After I finished the installation and refilled and burped the cooling system , the engine ran fine. Great experience with CY, not so much with CD.
I need to be planning toward a replacement of my exhaust elbow and associated parts. My boat is 16 years old, and I can find no reference to replacement or inspections by prior owners. (May be missing some service records.) I'll be putting an IR gun on various parts (exhaust hose, etc.) to look for hot spots or other signs of leaks or plugging. I've seen no sign of steam in my exhaust or anything, just concerned over age. My concern is that once I start ripping off insulation I may want to have all the replacement parts handy so I don't lose out on any of our too-short season.
Is the general consensus to buy the nice electropolished one from CD (and pay for the overpriced insulation kit) or to get the one from CTY with the free DIY wrap?
Quote from: Breakin Away on July 13, 2017, 08:27:13 PM>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
Is the general consensus to buy the nice electropolished one from CD (and pay for the overpriced insulation kit) or to get the one from CTY with the free DIY wrap?
This is not a consensus issue, it is a personal choice issue. In my muffler and exhaust riser replacement tech note (Feb. 2016) I discussed the choice I made and why.
Your boat, your choice. :D
Quote from: Stu Jackson on July 14, 2017, 06:43:49 AM
Quote from: Breakin Away on July 13, 2017, 08:27:13 PM>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
Is the general consensus to buy the nice electropolished one from CD (and pay for the overpriced insulation kit) or to get the one from CTY with the free DIY wrap?
This is not a consensus issue, it is a personal choice issue. In my muffler and exhaust riser replacement tech note (Feb. 2016) I discussed the choice I made and why.
Your boat, your choice. :D
I disagree. Of course it's ultimately my choice, but what does this forum exist for, if not to compare recent experiences of people with similar boats? I am not obligated to go with any consensus (my choice), but if there is an emerging consensus, I think this is the place to communicate it. And if there is no consensus, open discussion among many owners will be useful to all. So my question still stands as originally asked, for those willing to participate.
I had seen your tech note, and this is what you said about getting the riser from Catalina Yachts:
QuoteI didn't price this from Catalina Yachts this time.
So I don't see much detail there about your rationale for a choice.
What I do see here is some signs of recent concerns over CD's pricing and customer service. So I think it's worth hearing more about this if people are willing to share, especially since the last time you checked with Catalina Yachts appears to be 2003. A lot has changed since then with both CTY and CD, including a 3x price increase at CD.
Also, please note that my boat is a MkII, so the parts we are talking about are different. It is possible that the optimal selection may be different for the different boats.
Consensus means agreement or accord. There were 1,801 Catalina 34s built. All of them had to have replaced their exhaust risers. Are there statistics on what route they chose? No. I have been an owner since 1998, Association Secretary since 1999, and was gifted by my PO with every single issue of Mainsheet magazine from 1987 on, when C34 articles were first written. I read them all, developed the Tech Notes Index and worked with your officers to put the tech notes online. There has not been a consensus on where to source replacement risers, ever. And you're actually missing a choice: making your own. This option was discussed early on in the old FAQs: http://www.c34.org/faq-pages/faq-exhaust-pipe.html (http://www.c34.org/faq-pages/faq-exhaust-pipe.html)
And whether the boat is a Mark I or II is also immaterial. The concept is identical.
My Feb. 2016 tech note article also discussed the fact that I DID buy my first replacement riser from Catalina Yachts and mentioned an earlier tech note I wrote about that experience. ("My own February 2004 Tech Notes discussed our first riser replacement at 1,390 engine hours.") So there was more discussion than your reply indicated. And, yes, I chose to not use CY this time. But that would not preclude anyone from doing a simple price comparison between the two, would it? CD's price is online, I suppose one would have to call CY to ask.
I know what forums are for and applaud your participation and contributions here. I offered my opinion, based on what I have learned in nineteen years of ownership and literally daily reading of this forum.
There are a few items in which consensus is a valuable indicator. Issues like using a hump hose to your muffler and replacing the exhaust hose come to mind.
Choice of a source for exhaust risers, IMHO, isn't one of them.
Why? Because they are both quality products. The difference (might be) cost, and availability. I got good service from CY 15 years ago. I did not have the luxury of waiting this time around, so went with CD who delivered the product to me in Oakland from Sacramento in one day. I was willing to pay what I perceived to be a higher price because of that fact. But my tech note article did also say that I got essentially a free muffler, so that overall cost total factored into my decision making.
Thanks for your opinion, Stu. I appreciate it. I'll continue to track down additional sources of information while I await other opinions here.
Questions: is it prudent or premature to change out the riser and its elbow before they fail? Are there warnings to look for that indicate failure is eminent?
Quote from: Noah on July 14, 2017, 12:14:20 PM
Questions: is it prudent or premature to change out the riser and its elbow before they fail? Are there warnings to look for that indicate failure is eminent?
That is a very good question, and I look forward to answers from others who know more than I do.
I am just beginning with this, and have not done a visual inspection yet. But with the boat 2 hours away, I always try to do my homework before heading to the boat. For starters, I plan to put a laser/IR temperature gun on the exhaust hose to look for hot spots. Ditto for the insulation - if there's hot exhaust or moisture seeping out from a micro-crack, I would think it could show up as hot spots. (These were suggestions that I picked up from various print and web resources.) I have no exhaust odor to indicate any problems at this point.
The sole reason for my concern is the age of my boat. Previous owner had the boat for 8 years, and wasn't much of a DIYer, but he had lots of receipts for work orders. There's no mention of him paying for an inspection or replacement. So it's time for me to look into this proactively.
Breaking : What are your engine hours??
A riser deteriorates from USE? It will usually fail at a welded jount or especially where the raw water from the HX squirts into the riser joining with the hot exhaust gases.
What Stu is trying to tell you - is not to throw parts at the engine as a "just in case"! A riser failure starts with a small leak usually of the water in the exhaust.
To ease your worry, take off the heat barrier insolution and inspect the riser. You can always reinstall that wrapping!!
A few thoughts
Very good questions from both BA and Noah.
Many years ago, then C34IA Commodore Dave Davis attempted to try to pin down the engine hours where these things failed. It was a fruitless endeavor, because as Ron said, it is due to USE but varies between boats because the quality of the weld varies from riser to riser. In my 2003 experience, that's where it broke, and IIRC, I included pictures of the broken riser in that referenced tech note.
And that's where 99% of the ones I heard about have broken. Why? 'Cuz it's just like the weakest link in the chain story as Ron said --- it's the NASTIEST place on the boat: gee, hot gas and hot water mixing.
THAT is where to look, right above the hump hose.
I, too, BA, had copious notes and details from our meticulous PO, but no indication that the riser had ever been replaced.
To Noah: when I replaced the muffler, I included in that referenced 2016 tech note the fact that I bought a new riser "since we were in there anyway." I also include the engine hours for my first 2003 failure and those in 2016. I forget the exact numbers, but they are there.
Quote from: Noah on July 14, 2017, 12:14:20 PM
Questions: is it prudent or premature to change out the riser and its elbow before they fail? Are there warnings to look for that indicate failure is eminent?
Yes, it certainly would be, because your engine is operating WHEN (not if) it fails. Think about it, right? In 2003, I described the huge plume of brown smoke & soot. Hell, if I'd been proactive and replaced it first, I wouldn't have had to spend four hours sailing home against the current (for a one hour trip!) and wouldn't have had the boat unusable for a long time. I could have CHOSEN when to do the work. Which is exactly what I did 13 years later. :D
And IIRC both of my tech notes quote and/or refer to Ron Hill's excellent earlier writeups which helped me immensely.
BA, it's good that you ask these questions. And, as you said, the use of this forum has been to discuss these issues. I've always felt that by giving back and writing things up, we can help folks and "avoid reinventing the wheel."
I believe that between Ron's 1990s tech notes and my two, and that FAQ I lined to, we've addressed the issues in as much detail, with reasoning, experience, tips & tricks and explanations as we possibly could.
If you have more specific questions after reading those, please fire away, we'd be glad to expand on anything. :D
BA,
Something to think about re: fabricating your own (or having it fabricated). If you use pipe, especially Sch 80, it will be a lot more robust than the stainless tubing that CTY and CD, and (especially if electropolished) last much longer. Well, possibly except for the water injection where it fail fail anyway. So fabricating it with a threaded injection as the last fitting may, at least theoretically, allow that to be replaced when it fails. Of course your particular engine and MK will determine how much room you have to use threaded nipples/fittings, or if you need to use the pre-fab stainless tube riser.
(http://www.moyermarine.com/images/532.jpg)
kk