08 MCX Exhaust -- how hot is too hot?

[jsnipes]

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

[c_craig]

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.

[Engine Nut]

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

[kev88]

I purchased my 08 X-2 in September 07 - was prob. built in late July/August. Anyone had problems with an early build 08?

[jsnipes]

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

[fbroen]

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.

[Reto]

I have the same problems with my 08 X-2.

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

[TheOneandOnly]

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...

[jsnipes]

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]

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[TheOneandOnly]

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?

[c_craig]

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!

[mbtka]

I believe mine was built in Nov/Dec as well.

[jsnipes]

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]

I am going to ask my dealer as well when I pick up the boat on Thursday.