PDA

View Full Version : 08 MCX Exhaust -- how hot is too hot?


fbroen
03-23-2008, 09:33 PM
Did maiden voyage today on our 08 X1, just tooling around getting some hours on engine.

Noticed that the exhaust hoses connecting the ETX/CATs to the exhuast tips get REALLY hot when at speed (3000 rpm). Realizing that the Cat's will run hotter than tradional exhausts, but:

- too hot by far to hold hand on by connection to manifold,
- hot enough to make exhast hose soft and collapsible,
- hot enough to smell like burnt rubber.

Is this normal ?!

Other circulating hoses seemed fine, engine running normal temp. Thanks.


One side even kinked a bit from getting soft from the heat:

http://i193.photobucket.com/albums/z112/fbroen/hot_area.jpg

skeeler
03-23-2008, 09:40 PM
I noticed on the '07 X-2 we had, that it also got very hot. Gauge read normal, but when you popped the engine compartment you knew it had to be way warmer than what it was reading. I never really looked that close to mine to see if it was bending.

CottagerGreg
03-23-2008, 11:55 PM
I don't think there would be any issues, exhaust is going to be hot.. come on, it's comming out of a engine.. just make sure the water injection is working.

Ski Bum
03-24-2008, 01:11 AM
Water temp wont have much indication on how how the exhaust is getting. Exhaust temp can run up to 1200 deg. before melt down give or take 50. this is temp should be taken about 2" out of the Exhust port on the mainifold take a temp gun and shot it and I bet its not over 900 deg.

TMCNo1
03-24-2008, 07:37 AM
Most every V-Drive boat I have ever see on the production line @ MC has a kink in the rubber pipe between the exhaust manifold/muffler/thru hull exhaust fitting, because of the angle of the approach. Until a form fitting metal or fiberglass pipe with a radius is used with a short rubber joint each end, there may be a kink in those hoses I would guess. Apparently MC engineering/Indmar doesn't think it hinders the performance. Maybe someone from the MC factory can elaborate on this. Is it done like that by other boat manufacturers.

fbroen
03-24-2008, 08:41 AM
Thx guys for the feedback.

I should have been more clear in my original post -- not worried that the exhaust is too hot per se – I AM concerned that there is sufficient water cooling at the tip of the manifold so that the hose will be able to withstand it.

Mentioned engine water temp only as indicator that the rest of the cooling circulating system seems to working just fine.

Ski Bum, are you saying that the exhaust hose is supposed to be able to withstand 1200 degrees? I tried to look at some SAE specs but came up with much lower numbers (but must confess to not knowing much about it.

Coming from two TBIs with regular manifolds and risers, this heat is whole new territory -- just trying to figure out if normal / safe to run?

Thanks again.


Oh, and mentioned the kink as it only appeared after running -- after it smelling like melted rubber and actually smoking a bit on the outside of the hose. The starboard side was very hot too, but still looks the same, without kink:

http://i193.photobucket.com/albums/z112/fbroen/no_kink.jpg

TMCNo1
03-24-2008, 09:48 AM
I can say, it looks better w/o the kink!

vision
03-24-2008, 04:15 PM
I have an 08 X-star MCX and it it likewise is warmer at the end of the CAT than my 05 X-2 MCX. I am told by an auto engineer that I know that many catalytic converters require temps near 1000F to work efficiently and that after looking at the Indmar/MC set up in my boat, he predicted that the temp coming out the CAT would be around 500F.

Ski Bum
03-24-2008, 09:59 PM
Yes that temp will melt the rubber hose. The 900 deg to 1200 deg is 2" out of the exhaust port. Water is injected after that to cool it down. I would fire it up on land with a flush kit. Make sure water is coming out the tail pipes. If not you have a problem and contact MC.

fbroen
03-27-2008, 11:30 AM
Thx. Yeah, water is coming out of the tailpipes. Everything seems to circulate fine.

Just shocked about how hot the exhust hoses get on the CAT system -- but this does appear to be how it is all designed.

Big change from the traditional setup for sure.... Seems like manual should include something aliong the lines of, "Don't worry if you think the exhaust hoses will melt -- this is just the way it is now...." ;)

ncsone
03-27-2008, 11:42 AM
Side note - its interesting that the cats are so hot and right next to the air intake. Would be nice to see a fresh air source so that the intake air is not so hot. Would probably be a nice bump in HP with a cool intake charge vs. the hot air.

Jim@BAWS
03-27-2008, 11:42 AM
Thx guys for the feedback.

I should have been more clear in my original post -- not worried that the exhaust is too hot per se I AM concerned that there is sufficient water cooling at the tip of the manifold so that the hose will be able to withstand it.

Mentioned engine water temp only as indicator that the rest of the cooling circulating system seems to working just fine.

Ski Bum, are you saying that the exhaust hose is supposed to be able to withstand 1200 degrees? I tried to look at some SAE specs but came up with much lower numbers (but must confess to not knowing much about it.

Coming from two TBIs with regular manifolds and risers, this heat is whole new territory -- just trying to figure out if normal / safe to run?

Thanks again.


Oh, and mentioned the kink as it only appeared after running -- after it smelling like melted rubber and actually smoking a bit on the outside of the hose. The starboard side was very hot too, but still looks the same, without kink:

http://i193.photobucket.com/albums/z112/fbroen/no_kink.jpg


What you are smelling IS NOT the rubber hose. What you are smelling is the UNIQUE smell of engine paint getting hot and setting into the motor. It will last for the first 5-8 hours as the motor gets hot then cools. I had the MCX in my X-1 same set up. Ran for 100 + hours last year. You won't have any problems. That engine paint smell is normal. Always reminds me. THIS IS A NEW BOAT. Sort of like that NEW CAR SMELL that only last for about a month or so.

Jim@BAWS

jweischen
03-27-2008, 03:53 PM
JimBaws:

Note fbroen's later comment -
"Oh, and mentioned the kink as it only appeared after running -- after it smelling like melted rubber and actually smoking a bit on the outside of the hose. The starboard side was very hot too, but still looks the same, without kink:"

He observed smoke off the hose.

I have an '08 X2 (RTP 1) and may also have experienced this problem. Smell is not engine paint, but more of a burnt rubber smell. I will check it out next week when I fire up the boat after winter.

fbroen
03-29-2008, 09:18 PM
Hours 3-7 on the engine today. Smoke on outside of hose will develop any time running at 3000 rpm or above for a while. (See below by hose clamps)

Hoses are nice and cool about 6-8 inches below the top, so cooling defintively circulating. Looked at the tips under way today, and lots of water is gushing out.

Smoking hoses just part of the CAT setup... :confused:

http://i193.photobucket.com/albums/z112/fbroen/IMG_1382.jpg

TheOneandOnly
03-29-2008, 09:42 PM
smoking of the hose does not seem normal...

jsnipes
04-20-2008, 09:32 PM
I took the maiden on my 08 X-2 today and observed similar smoking of the rubber hose and smell. I kept a close eye on it and all seemed OK. I made frequent inspections in the engine area and stopped often to let the engine idle and cool down, per break in procedure.

I followed the break in procedure and at about 4 hours I noticed that the engine seemed to be "lope-ing" ... sounded like a hot rod car. I took a look under the engine cover and found that a hole had formed on the starboard hose just below the clamp. I was close to the marina and took it in ... a little bit of exhaust was being shot onto the plastic side wall of the engine compartment. We'll see what the dealer says tomorrow.

No issues otherwise ... I could tell when the hole formed by the sound. Engine temp never went over 160. Otherwise a great day out. Kinda makes me disappointed in MC though.

Anyone else have any other observations?

JS

jsnipes
04-20-2008, 09:32 PM
sorry, double post.

Holman J.B.F
04-21-2008, 02:17 AM
last week we took my friends 08 x-15 with a mcx ,it took about 1 hour before the exhaust hose had a big hole in it.It is stil at the dealer.
1.5 hours never got above 160.port side hose right after the cats on the left side.(seen from the platform)

TMCNo1
04-21-2008, 08:04 AM
I took the maiden on my 08 X-2 today and observed similar smoking of the rubber hose and smell. I kept a close eye on it and all seemed OK. I made frequent inspections in the engine area and stopped often to let the engine idle and cool down, per break in procedure.

I followed the break in procedure and at about 4 hours I noticed that the engine seemed to be "lope-ing" ... sounded like a hot rod car. I took a look under the engine cover and found that a hole had formed on the starboard hose just below the clamp. I was close to the marina and took it in ... a little bit of exhaust was being shot onto the plastic side wall of the engine compartment. We'll see what the dealer says tomorrow.

No issues otherwise ... I could tell when the hole formed by the sound. Engine temp never went over 160. Otherwise a great day out. Kinda makes me disappointed in MC though.

Anyone else have any other observations?

JS


We need pictures so we can see the smell of the new paint, "New Boat Smell" and all the other stuff that makes the hole in the exhaust hose.

Roonie's
04-21-2008, 10:02 AM
I know on my 07 X2 the exhaust hose in kinked similar to your pic. No problems on holes as I have about 40 hours on it now and don't expect any problems. No burning rubber smell either just the burning paint smell described by Jim. Maybe a new problem with the 08's?

jsnipes
04-21-2008, 02:17 PM
Funny, TMCNo1!

I just spoke with my dealer and here's what he said ... I can only assume that this is accurate.

He has seen a hole develop in one other boat. The issue appears to be due to a lack of enough water flow to keep the manifold below "rubber burning" temps. The lack of water flow stems from a weld that was added in the manifold ... the sensor on top of the manifold needs to stay dry and they added an inner thin wall tube to accomplish this. If the weld is not to spec then it can restrict flow. He was not sure of the scope of the issue ... he's only seen it once before and MC has issued no service bulletins, etc. The first go around they just replaced the rubber exhaust hose which burnt through again (of course). He has since worked with MC to either replace the manifold or else fix the weld in it (not sure which was done). He is going to work with MC on mine this week to determine the course of action and get the part in to do the job.

I'll post what comes of this, but I'm glad that at least my dealer recognizes that there is a technical problem and is not just going to throw another hose on it. I'm disappointed that MC did not test waterflow through the manifold or else identify a potential problem on the water test. I mean, c'mon ... exhausts get hot ... it doesn't seem to hard to me to avoid this problem.

Still an MC fan, a little disappointed that my boat with less than 4 hours is headed back to the shop.

JS

fbroen
04-21-2008, 02:31 PM
Thx folks for posting. Pls keep us updated.

Ours now has 11 hours on it. No hole in exhaust hose yet. Although by the looks of it in the kink, I fully expect a hole to develop sooner or later -- so, very interested in you all's developments.

Had ours break-in serviced, and hooked up to computer. No codes, and tech said he has seen the kinks elswehere, but no failings. Yet -- would be my guess.

c_craig
04-27-2008, 09:14 PM
I mentioned this somewhere else, but same thing on my '08 X-15 today. 2.5 engine hours, our second brief trip to the lake, and we burned a hole in the port exhaust hose. Dealer was on the lake doing demos, so they looked at it right away. He thinks the manifold elbow is bad and needs to be replaced. Thinks the exhaust water is not circulating evenly, causing a hot spot on the hose. Interesting, he guessed "port side hose" as he approached the boat, and later said that seems to be more common, port side is always hotter?

vision
04-28-2008, 01:47 AM
08 X-star with MCX. No holes in rubber exhaust tubes so hopefully ours will not develop this problem. But, several other minor to perhaps major (transmission) problems by 40 hours. I have to agree that for 08, MC quality control seems to have slipped. I had 500 hours on an 05 X2. Never a single problem. Love my MC, great dealer, but it is frustrating to lose lake time due to problems with a new boat.

mbtka
04-28-2008, 10:22 PM
Seem's like this might be a problem. We are picking up our boat on Thursday and will see if we have the same problem with our MCX.

erkoehler
04-28-2008, 10:36 PM
Should be a service bulletin along shortly from the sounds of it :(

We've had 1 boat come back as well.

TheOneandOnly
04-28-2008, 10:56 PM
ERk-- we have 2.5 hrs on ours also 08x2, is this going to be a recall? Id like to get ours in if they need to change something especially since the weather is still crappy here in mn. Thx

erkoehler
04-28-2008, 10:57 PM
Just keep an eye on it, they haven't released a bulletin/recall as of yet. Stay tuned!

mbtka
04-28-2008, 10:58 PM
Have you had any problems with your's yet? This weather in MN is rediculous.

TheOneandOnly
04-28-2008, 11:16 PM
Actually havent looked although Id only assume if there is a heat issue coming out of the exhaust its only a matter of time.

Does water come out of that hose? I really do not want to just keep an eye on it especially if it could cause some safety hazard for our family. If in any way it could cause a issue we will just wait until its fixed.

MN weather really makes us wonder why we still live here only 3 mths of warm weather id agree rediculous...

ERk is it on all mcx engines or just some?

c_craig
04-29-2008, 07:10 AM
Yes. Water and exhaust mix comes out of that hose (and into your engine compartment when you get a hole). Roll of duct tape would have been nice to have on the water. There's a thread for that too right? Another question I heard. Does the increase in exhaust temp cause a problem in the engine compartment? Is there enough fresh air moving through to keep the temp in check? I assume you can't / shouldn't run the blower all the time, or I'll be buying blower motors in bulk... Like the thing under my name says, "TT Newbie". We've been driving boats ('89 Tristar and others) for years, but this is our first as an owner.

TheOneandOnly
04-29-2008, 09:40 AM
Yes. Water and exhaust mix comes out of that hose (and into your engine compartment when you get a hole). Roll of duct tape would have been nice to have on the water. There's a thread for that too right? Another question I heard. Does the increase in exhaust temp cause a problem in the engine compartment? Is there enough fresh air moving through to keep the temp in check? I assume you can't / shouldn't run the blower all the time, or I'll be buying blower motors in bulk... Like the thing under my name says, "TT Newbie". We've been driving boats ('89 Tristar and others) for years, but this is our first as an owner.

Roll of duct tape, I thought that was only used on bayliners? I run the blower all the time will not hurt anything its just a fan.
Ccraig what model/yr boat?

c_craig
04-29-2008, 02:56 PM
'08 X-15. Thanks for the info.

erkoehler
04-29-2008, 03:27 PM
Actually havent looked although Id only assume if there is a heat issue coming out of the exhaust its only a matter of time.

Does water come out of that hose? I really do not want to just keep an eye on it especially if it could cause some safety hazard for our family. If in any way it could cause a issue we will just wait until its fixed.

MN weather really makes us wonder why we still live here only 3 mths of warm weather id agree rediculous...

ERk is it on all mcx engines or just some?


Check with your local dealer, they'll be able to look at your boat to see if it has a problem.

As far as I know it is only SOME boats w/ the MCX experiencing issues.

jkski
04-29-2008, 03:31 PM
'08 X-15. Thanks for the info.

C Craig,

You have a great looking boat and the people at Boat House Marine will make sure it is right. It's nice to have such a great dealership that knows the problem and can fix it on the spot.

jsnipes
04-29-2008, 10:47 PM
My dealer said yesterday that they will be replacing the manifold on the side I was having problems on...the problem sounds like it's manifold specific as far as the weld tolerance so one side could be OK and the other side not. I'll let everyone know the results ...

Jamie

mbtka
04-30-2008, 12:28 AM
I am going to ask my dealer as well when I pick up the boat on Thursday.

jsnipes
04-30-2008, 12:45 AM
My advice is this ... if you start smelling burnt rubber and see wisps of smoke coming from one of the hoses, head for the marina and get it back to the dealer. I had an '06 X-15 from new and it never smelled that way. It had an MCX, but no cats. I can not say that the smell was exclusively coming from the "bad" side, but I can say that the only side with wisps of smoke was coming from the "bad" side. As you would expect, the smell and smoke was worst just after several minutes of running at speed. When I would pull back to idle to let the engine cool down the smell would become evident and I would open the engine cover and see the smoke ... just very small wisps of smoke, but noticeable. After idling for a few minutes the smoke would go away fairly quickly and the smell get less strong.

When the exhaust hose blew it was a very noticeable difference in sound at idle. It sounded more "hot rod" like. I didn't notice it while running ... only when I pulled back to idle. The amount of water coming from the hole was very minor .... mostly exhaust and a little water (probably some steam) hitting the plastic side wall of the engine compartment. It scarred up that plastic panel a little but not bad. The hole was pretty much straight sideways so nothing blowing up into my face or anything, but the hole could form in any orientation I guess.

Best of luck with yours ... it may be just fine. Mine was built in Nov/Dec '07 by the way. Maybe later ones are of less risk?? For those who have the issue, when was yours built?

Jamie

mbtka
04-30-2008, 12:47 AM
I believe mine was built in Nov/Dec as well.

c_craig
04-30-2008, 07:29 AM
Our dealer mentioned the same issue about welds and replacement of the manifold or related parts, but we're waiting to see right now. Are cats new to these engines? If so, when? Is that what causes such high exhaust temps? Same things when our hose opened up, mostly exhaust and just a little water spitting out the hole, which also led the dealer to believe the water is not circulating properly in the exhaust. With a hole in the hose, there should be substantial water coming out, like out the tail pipes I assume. We actually lost power when it went, like PP was stuck at 10 MPH. I was in the bow and did not notice the change in engine sound until I got behind the windshield. Either way, you'll know. We idled in with a sort of "Cigarette" sound to it!

TheOneandOnly
04-30-2008, 09:19 AM
My advice is this ... if you start smelling burnt rubber and see wisps of smoke coming from one of the hoses, head for the marina and get it back to the dealer. I had an '06 X-15 from new and it never smelled that way. It had an MCX, but no cats. I can not say that the smell was exclusively coming from the "bad" side, but I can say that the only side with wisps of smoke was coming from the "bad" side. As you would expect, the smell and smoke was worst just after several minutes of running at speed. When I would pull back to idle to let the engine cool down the smell would become evident and I would open the engine cover and see the smoke ... just very small wisps of smoke, but noticeable. After idling for a few minutes the smoke would go away fairly quickly and the smell get less strong.

When the exhaust hose blew it was a very noticeable difference in sound at idle. It sounded more "hot rod" like. I didn't notice it while running ... only when I pulled back to idle. The amount of water coming from the hole was very minor .... mostly exhaust and a little water (probably some steam) hitting the plastic side wall of the engine compartment. It scarred up that plastic panel a little but not bad. The hole was pretty much straight sideways so nothing blowing up into my face or anything, but the hole could form in any orientation I guess.

Best of luck with yours ... it may be just fine. Mine was built in Nov/Dec '07 by the way. Maybe later ones are of less risk?? For those who have the issue, when was yours built?

Jamie


We did notice ours last week when we only put 2.5hrs on it it started to get more raspy, I was like cool it must be just getting somewhat broke in... Now we have to go look to see if it was melting...

Ours was built in Nov/Dec 2007... Wonder if we have a bad one also, wont be able to forsurely know until its gets nicer out.

Is it a extensive down time labor project?

TheOneandOnly
04-30-2008, 09:19 AM
.....................................

jsnipes
04-30-2008, 12:48 PM
I think the cats started in '07. My '06 did not have them. Not sure why we are just seeing this. Maybe there was a manifold design change.

I know what you mean on the "cigarette boat" sound. Was cool for a few seconds until I realized that there must be a reason for it!

JS

TheOneandOnly
05-02-2008, 08:27 PM
Ours will more than likely fall into needing to be updated, going back to be inspected next week. Not a big deal though since the weather here in MN ***X...

Reto
05-06-2008, 05:03 PM
I have the same problems with my 08 X-2.

A hole in the starboard exhaust hose. :( 10 hours young.

fbroen
05-08-2008, 04:16 PM
My understanding is that there is now a formal recall out to get this issue addressed for certain serial numbers. So if you are smelling burnt rubber you may want to see if yours is covered.

Our boat had insufficient tolerances and exhaust elbows will be swapped out. I am very happy to get this issue taken care of and put to bed.

Oh, and ours is a late 07 build as well.

jsnipes
05-09-2008, 06:33 PM
I'm picking mine up tomorrow after the repairs. They replaced both manifolds and at least one if not both hoses. Only one side was having the problem but they wanted to play it safe, although maybe the recall has them doing both regardless. I'll let you all know how it goes. Seems like a well understood problem and I expect no more issues.

The dealer said that they did a water flow check on the old and new manifolds and the difference is clearly obvious. Said he would show me the bad one.

Hats off to how Carolina Mastercraft has handled this issue that was not their fault. MC should have caught this with either a water flow test of the manifolds or worst case on the water test of the boat. Tssskk, Tssskk!

Jamie

kev88
05-10-2008, 09:55 AM
I purchased my 08 X-2 in September 07 - was prob. built in late July/August. Anyone had problems with an early build 08?

Engine Nut
05-10-2008, 12:38 PM
I purchased my 08 X-2 in September 07 - was prob. built in late July/August. Anyone had problems with an early build 08?

Let me clear the air on this issue. We issued a service bulletin to the MasterCraft dealers asking them to inspect the exhaust elbows on a group of 2008 model MasterCraft MCX engines starting with engine serial number 144278 and ending with serial number 146784. Some of the engines in this group may have been built with exhaust elbows that have restricted water passages that will not allow sufficient water flow to cool the exhaust hoses adequately. This is issue didn't show up at our end of line test at Indmar or at MasterCraft's lake test because the engines are not run long enough or under the right conditions to have the problem occur.

Inspection is simple. We have provided a measuring tool to the dealers to allow them to remove the exhaust hose and measure the gap between the inner and outer wall of the exhaust elbow. If the gap is too small, they are to replace the elbow. The whole process is pretty simple. If you have an engine in this group and already have some hours on it without experiencing a problem, your exhaust elbows are probably just fine. Most of the failures we have seen have occurred in the first 10 hours of operation.

Indmar is very sorry about this situation. We are dedicated to provide our our customers withthe best products possible. Unfortunately when you are on the leading edge of technology, unexpected problems occur.

Larry Engelbert
Director of Customer Service
Indmar Marine Engines

c_craig
05-11-2008, 12:45 AM
Back out today with the new exhaust elbow. Absolutely no problems. Heard from the dealer that Indmar is handling this all the way. Thanks Larry.

jsnipes
05-12-2008, 10:10 AM
Thanks for providing the information, Engine Nut! I think most of us know that problems can and do occur ... the key is communication. Updates like yours on this site and the service bulletin issuance go a long way toward maintaining consumer confidence through situations like this. I appreciate your willingness to bite the bullet.

On a related note, I picked my X2 up on Sat and spent several hours out with no problems after the "fix". Both exhaust elbows on my MCX were changed out. There was zero burnt rubber smell. So ... if you have an MCX and smell any hint of burnt rubber don't wait for the hole to form in your hose. Get it in to the dealer for the warranty repair!

I would like to note that I incorrectly have been saying "manifold" instead of exhaust elbow in my previous posts on this thread. Sorry for any confusion this may have caused.

I think this is a closed case for me. Great job Carolina Mastercraft on handling the issue very quickly and efficiently, even before the service bulletin was issued.

Jamie