Blown muffler rebuild - Easy
Printed From: CorrectCraftFan.com
Category: Repairs and Maintenance
Forum Name: Boat Maintenance
Forum Discription: Discuss maintenance of your Correct Craft
URL: http://www.CorrectCraftFan.com/forum/forum_posts.asp?TID=17967
Printed Date: January-16-2025 at 3:51am
Topic: Blown muffler rebuild - Easy
Posted By: Scrawford
Subject: Blown muffler rebuild - Easy
Date Posted: June-08-2010 at 1:30pm
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I wanted to share with members my recent experience regarding the Hull Hugger muffler on my 97 SN.
Over the weekend I noticed a crack (and water leak) in the muffler. Upon pulling it Sunday night I found out that the bypass tube inside came loose. After almost having a heart attack over the $550 cost for a new one, I decided to rebuild it myself. I'll post the details in a couple weeks after I confirm that it worked, but basically I cut an access hole on the larger side, re-epoxied the tube in place, then rebonded the piece I cut out. It looks good this morning and I am going to give it a try tonight. Total cost about $35 and 2 hours. If it works that makes for quite a bit of beer money... ------------- Eric 97 196 Closed Bow |
Replies:
Posted By: Scrawford
Date Posted: June-09-2010 at 12:36pm
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So the repair worked perfect. Patched it up with 2-part epoxy and glass weave from Lowe's. MAKE SURE AND CUT YOUR ACCESS HOLE AT A 45 DEGREE ANGLE. The muffler is made up of two layers of glass with a layer of rubber in-between. If you cut straight down through the glass the inner layer won't be able to be reset. I cut a square about 6" x 12" on the top of the larger side and it worked perfect. If anyone has any specific questions let me know. ------------- Eric 97 196 Closed Bow |
Posted By: M3Fan
Date Posted: June-09-2010 at 1:04pm
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I'd be really interested in seeing some pics. ------------- 2000 SN GT40 w/99 Graphics/Gel 2016 SN 200 OB 5.3L DI https://forum.fifteenoff.com |
Posted By: Scrawford
Date Posted: June-10-2010 at 2:57am
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Unfortunately in the haste of the rebuild I forgot to snap photos. Super easy though, but easier than planned. If anyone is thinking of doing it just PM me and I can walk you through it or discuss on the phone.
Scrawford ------------- Eric 97 196 Closed Bow |
Posted By: AussieNorts
Date Posted: September-16-2010 at 3:48am
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hey i know you posted this ages ago but i have a question, i also have a 97 sport, i have to pull my hull hugger as i have a leak there somewhere also. I noticed last night when looking around it that it has worn the fibreglass underneath it(the Hull) especially under the corners of the hugger. Did you have this issue? Not sure if i have to just get some rubber mat for it to stop the rubbing between it and the hull, or do i also have to repair the hull as well? Any thoughts would be greatly appreciated. ------------- Correct craft.....is there any other boat? |
Posted By: Chopper
Date Posted: September-16-2010 at 5:36am
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Hey Steve,
Your muffler should not be sitting directly on the inside hull. It should have some rubber pads attached to the underside to separate it and prevent wear from vibration etc. You may have worn thru a corner of the muffler or it could be split on the underside. Is that your 97 I noticed on boatpoint today.? ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=1540&sort=&pagenum=2&yrstart=1996&yrend=2000 - 98 Ski |
Posted By: AussieNorts
Date Posted: September-16-2010 at 8:59am
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i Had it on boat point but took it off, i couldn`t find it when i looked for it. Hope they took it down as i have a shed for the boat now and am starting to do a lot of work on it. I may need to ask you some more questions in the future, sounds like you have done heaps to you ski. I plan on doing interior soon. ------------- Correct craft.....is there any other boat? |
Posted By: Scrawford
Date Posted: September-16-2010 at 1:41pm
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No, I didn't have that problem, mine was all on the top. Yes, you should have some low durometer rubber between the hull hugger and the hull (I'd check McMaster Carr). Since glass repair is so easy (when non-cosmetic), I would go ahead and pull the muffler and repair it, just to make sure. It will cost you about $20 and could prevent catastrophic failure of the muffler.
By the way, my first post I said to use the 2-part epoxy from Lowe's. I now wouldn't recommend it. I just had to repatch mine because the muffler started to crack on the top. This time I used the standard lay-up resin from an auto parts store and its looks good (see attached). For those that have never done glass repair, here is the general process: 1. Rough surface with sandpaper to remove paint and sheen 2. Pre-cut the woven fabric to the specific size required 3. Mix resin with hardener (~15 work time once mixed) 4. DO NOT ADD EXTRA HARDENER! 5. Using a stiff brisled brush, apply a liberal coat of resin 6. Lay on glass weave, and tap in place with brush (no add'l resin at this time) 7. Once weave is fully saturated, apply another coat of resin over the top 8. Be sure to work out bubbles with brush, as bubbles in resin will cause premature failure 9. If patching corner, cut slot in fabric so that fabric will lay flat against existing material. Good luck! Any questions let me know. ------------- Eric 97 196 Closed Bow |
Posted By: Scrawford
Date Posted: September-16-2010 at 1:47pm
Here is a picture. ------------- Eric 97 196 Closed Bow |
Posted By: Scrawford
Date Posted: September-16-2010 at 1:47pm
And another.
 ------------- Eric 97 196 Closed Bow |
Posted By: AussieNorts
Date Posted: September-18-2010 at 5:39am
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I have removed the hull hugger today and havenoticed how much it has worn. Also under thehugger was very worn so i have repaired with poly resin and fibre sheet. I will post some photos, of the repair job on the hullhugger and the need of repair of the hull, does anyone have any suggestions about repairing the hull? e.g. what i should use etc.. any help would be greatly appreciated, i wanted to have her back on the water next weekend.
Any guidance from the experienced guys here is always great thanks again. Steve    ------------- Correct craft.....is there any other boat? |
Posted By: Scrawford
Date Posted: September-18-2010 at 10:30am
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I think you got it. I would fade the area a little to allow the sheet to lay flat, then just use some resin and fabric. I would use the shredded fabric rather than than the braid, I think it would be a bit better choice for that area. ------------- Eric 97 196 Closed Bow |
Posted By: 8122pbrainard
Date Posted: September-18-2010 at 11:24am
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Steve,
From the pictures, to me it looks like only the decorative gel coating is worn off the hull. Personally, I wouldn't worry too much about it. ------------- /diaries/details.asp?ID=1622" rel="nofollow - 54 Atom /diaries/details.asp?ID=2179" rel="nofollow - 77 Tique 64 X55 Dunphy Keep it original, Pete < |
Posted By: AussieNorts
Date Posted: September-18-2010 at 11:37am
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So should I just paint some new gel coat over the exposed red areas? Another question, do I have to use a special paint to paint the hull hugger after the resin sets?
Steve. ------------- Correct craft.....is there any other boat? |
Posted By: 8122pbrainard
Date Posted: September-18-2010 at 12:56pm
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Steve,
You can put some new gel down if you want but as mentioned, it's decorative and I feel the muffler will cover up the worn spots. I'd just sand the gloss off the muffler repair and spray it with a aerosol can of semi gloss. Nothing special. ------------- /diaries/details.asp?ID=1622" rel="nofollow - 54 Atom /diaries/details.asp?ID=2179" rel="nofollow - 77 Tique 64 X55 Dunphy Keep it original, Pete < |
Posted By: winniskier
Date Posted: September-12-2011 at 9:25pm
The muffler in 1997 closed bow has a hole. It leaks like a fountain when the boat is at rest and sprays hot air and water when running. The crack is crescent shaped where the beautiful Carol Merril (hand in picture)is pointing. I am tempted to repair it, but only if I can be sure it will not repeat the same way or worse. The engine overheated and fried the first engine in 2000. This caused the port down tube to break under the clamps years after. I am thinking that the muffler suffered from overheating as well. Any idea why it would crack in this spot and what is going on?
 ------------- Jim |
Posted By: Scrawford
Date Posted: September-13-2011 at 1:55pm
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Jim - There is a ton of pressure inside the muffler when you bury the throttle from idle. This pressure is most likely what caused the crack. I would remove it from the boat and shake it to make sure that the bypass tube inside has not came loose (common problem).
ALSO, YOU CAN FIX THIS YOURSELF, IT IS EASY. Go to an auto parts store and pick up a fiberglass repair kit. This will contain resin, hardener, and woven fiberglass. I would avoid the random weave stuff as when it gets covered in resin the fibers start to come off. Also pick up a pair of plastic gloves, course sandpaper, and acetone. Here is the process: 1. Sand ALL the black off the area, the more the better. I would do an area at least 4" x 6", but 8 x 11 would be even better. If you have a vibratory sander or something similar that works great. Be agressive and make sure and sand into the glass a bit (you won't damage it). 2. Clean the area with Acetone and let it dry for at least 30-60 minutes. 3. Cut two pieces of glass slightly smaller than the cleaned area. This is important, DO NOT make it the same size as the cleaned area because you don't want any resin or fabric to extend onto the painted area because this will cause premature failure of the repair. 4. Mix the resin and hardener. Remember, you need to be completely done in about 15 minutes from this step. 5. Apply a coat of light resin to the surface. 6. Apply your first layer of fabric and using a tapping motion with the saturated paint brush work the bubbles out of the fabric. 7. Apply another coat of resin over the top so the surface is fully coated. 8. Repeat with the second layer of fabric. 9. Let cure for 24 hours before use. I would plan a total time of about four hours, easily done on a weekend afternoon. Good luck! If you have any questions just ask. All 4. ------------- Eric 97 196 Closed Bow |
Posted By: winniskier
Date Posted: March-24-2012 at 2:41pm
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I sanded off the paint. It appears that the hole is in a gap of a layer of cloth. It looks like a strip encircled the muffler, but was to short for the ends to touch. Yhe tubes are not loose, but the baffle is not secured, not very loose, but it moves a little. Is this normal or will this create issues down the line? ------------- Jim |
Posted By: SNobsessed
Date Posted: March-25-2012 at 12:50am
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If you can reinforce it, do it now! ------------- “Beer is proof that God loves us and wants us to be happy.” Ben Franklin |
Posted By: winniskier
Date Posted: March-25-2012 at 2:54pm
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I can't tell how the baffle is secured to the sides of the muffler. Looking from the tubes, I can see no adhesive or fiberglass connecting the baffle to the side of the muffler. From the hole, same thing. It looks like the the baffles slides into a channel on the inside of the muffler shell and that the channel holds it in place. I'd like to know before I cut into it to fix it. Any ideas? ------------- Jim |
Posted By: Scrawford
Date Posted: March-28-2012 at 9:14pm
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On my muffler the baffle is secured using two 'L' brackets between the tube and the upper and lower inside housing that is fiberglassed in place. If you have a hole fix it now. All you need to do is sand it down, clean it with some carb cleaner, then re-glass it. Let me know if you have any specific questions. ------------- Eric 97 196 Closed Bow |
Posted By: winniskier
Date Posted: March-28-2012 at 9:24pm
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Thank you. The concern is that the baffle seen through the hole is not secure. If it is attached by "L" brackets in other spots inside the muffler, then that would explain whi it does not seem to be attached near the hole. Does this make sense? ------------- Jim |
Posted By: Bri892001
Date Posted: March-28-2012 at 9:33pm
| Can you reach in and pull out the loose baffle? Probably better not too have it, then to have it get lodged somewhere undesirable. |
Posted By: winniskier
Date Posted: March-31-2012 at 7:31pm
I cut out a section with the hole. The baffle sits in a groove that is cut into the inside wall of the muffler. The baffle is not connected to the groove. Either by design or by wear, the baffle can move in the groove. This movement helped create the hole. The otherwise thick wall of the muffler is much thinner where the groove was cut. Plus, the spot where hole formed was in a gap of fiberglass cloth encircling the muffler at the location of the groove.  So my plan is to fill the gap created by the Dremel blade and the groove in the cut out section with fiberglass paste so the baffle will be held in the groove by fiberglass. This will stop the baffle from floating in the groove. Anyone think I should let it float? I can't think of a good reason. When this is all done, I would cover all of it with two or three layers of fiberglass cloth. Comments? ------------- Jim |
Posted By: C-Bass
Date Posted: April-02-2012 at 12:35pm
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Just get rid of the muffler altogether. ------------- Craig 67 SN 73 SN http://www.correctcraftfan.com/diaries/details.asp?ID=6103" rel="nofollow - 99 Sport 85SN |
Posted By: winniskier
Date Posted: April-02-2012 at 11:57pm
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I understand the sentiment, but I need to hear your reasons before I go spending $600 on a new one. ------------- Jim |
Posted By: Bri892001
Date Posted: April-03-2012 at 12:22am
He's most likely suggesting a Y-pipe conversion as discussed here: http://www.nautiqueowners.com/forum/forum_posts.asp?TID=14912&PID=172459&title=replacing-muffler-with-y-pipe-on-97-nautique" rel="nofollow - http://www.nautiqueowners.com/forum/forum_posts.asp?TID=14912&PID=172459&title=replacing-muffler-with-y-pipe-on-97-nautique It would cost a couple bucks to get the Y and you might need some additional exhaust hose, but still a lot cheaper than a new muffler. I was going to suggest this earlier, but I figured where you were going to so much trouble to fix the baffles, you must like the boat quiet. I'd be curious to see what it sounds like without the muffler. I'm kind of considering tossing my invertaflow in favor of the Y, but I do ski early in the morning on a small lake, so I figure I'll keep the muffler until it gives me problems. |
winniskier wrote:Posted By: Scrawford
Date Posted: April-03-2012 at 3:56am
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I would try the repair, as there is nothing to lose. I think you are right in putting some adhesive in there, just make sure to clean it all with a good decreaser (and give it time to outgas) before starting any repair. As for the y-pipe commonly discussed on these forums, I like my boat quiet so it has never been and never will be an option. Not that there is anything wrong with it though... Good luck! ------------- Eric 97 196 Closed Bow |
Posted By: winniskier
Date Posted: May-06-2012 at 9:57pm
Here it is repaired. ------------- Jim |
Posted By: Bri892001
Date Posted: May-07-2012 at 12:30pm
Good work, summer is fast approaching 
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Posted By: JoeinNY
Date Posted: May-07-2012 at 2:33pm
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That aught to do it Jim! ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=1477 - 1983 Ski Nautique 2001 1967 Mustang 302 "Decoy" http://www.youtube.com/watch?v=cO5MkcBXBBs - Holeshot Video |
Posted By: winniskier
Date Posted: August-21-2012 at 12:15am
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A swing and a miss: The repaired section held up great. However, an identical crack developed on the opposite side of the muffler. My guess is that the cracking is caused by the pressure, but I am not sure why it keeps happening in the same section of the muffler. As much as I hate admitting defeat, I am going to punt and buy a new one. ------------- Jim |
Posted By: TRBenj
Date Posted: August-21-2012 at 11:18am
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Probably just a weak point in the design... Id fix that new crack and run it. ------------- |
Posted By: ffhd1clt
Date Posted: May-28-2013 at 11:30pm
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I realize this is an old thread, but if anyone reads it, let me know what you think. I've read most of the comments, but i haven't heard anyone say they just removed the baffle, and then repaired the cracks and reinstalled the muffler. That is my plan, because the baffle is loose, and in my case would be a pain to repair. We cut a hole today, and we plan to cut out the baffle, repair the access hole and the crack in the muffler (reason it was taken out to start with), and reinstall the repaired muffler without the baffle. I'm guessing noise without the baffle will only be 10-15% louder than with the baffle, but that's just a guess. One thing is for sure, the muffler without the baffle will be much quieter than the "Y" pipe suggestion. Does anyone have experience with the hull hugger muffler (2 inlet/1 outlet) with the baffle removed? Thanks. ------------- Frankie @ LKN |
Posted By: jhersey29
Date Posted: May-12-2014 at 10:43pm
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I thought I'd share my experience. Here is a link to the video's on OneDrive. Thanks for the all info. I wouldn't have attempted this without running into this thread. http://1drv.ms/1nGGofy" rel="nofollow - http://1drv.ms/1nGGofy |
Posted By: Canuck-Surfer
Date Posted: January-04-2021 at 1:30am
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Before I start...everyone forgive me for resurrecting an ancient thread. My questions entirely are related to this repair thread so I didn’t want to start a new one. I have a 96 Sport with a leaking hull hugger muffler. It’s got a Centek label on it so I think it’s been replaced before and is not original. Because the pictures that were posted in the original thread are no longer available due to the web sight crash earlier this year, does anybody have any copies of pictures they can re-post to the thread? From the descriptions about doing the repair I still have no clear idea about where to cut into the muffler to attempt the repair. Maybe even a rough drawing somebody could snap a picture of an upload? Lastly, I have been strongly considering putting a fresh air exhaust system into this boat. If I cut the muffler open and remove the baffle, effectively turning the muffler into a glorified y-pipe and then install the fresh air exhaust, would the fresh air exhaust work as a muffler since the exhaust outlet would not be exposed to the air while under power? ------------- 1996 Sport Nautique GT40 EFI |
Posted By: jhersey29
Date Posted: January-04-2021 at 9:01am
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https://1drv.ms/f/s!AvCtCf0yHSvwj6BkzGN6y1O-fc9YjA Been a long time and don't really remember what I said in the videos. This was to repair the blown wall issue where it flapped. Might help. If it's just leaking I don't think you need all off this. Maybe just a hole worn through on the bottom from rubbing om the hull for years. |
Posted By: Canuck-Surfer
Date Posted: January-04-2021 at 10:29am
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Jim, these pics and videos are incredible. Like they say a picture is worth 1000 words! ------------- 1996 Sport Nautique GT40 EFI |
Posted By: jhersey29
Date Posted: January-04-2021 at 11:49am
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Getting the muffler out can be a nightmare. You might have to take off the risers. That leads into a whole other project if you break of any bolts and have to drill them out of the exhaust manifold. I got lucky on mine. Another friend had blown out the tubes that go from the risers down to the muffler. Both were leaking like crazy and one he over tightened and crushed. That ended up in 2 stuck bolts on 1 of his risers. One of them came out with a good soaking of Deep Creep. The other I had to cut off and drill out. It turned out well but was pretty darn scary and hard to get the drill bit centered. If you have to remove the risers don't forget to order the gaskets and that paint remover tool works great to clean up the riser and exhaust manifold.
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Posted By: slmskrs
Date Posted: January-04-2021 at 9:55pm
How'd you cut the top out of the muffler? It looks like an outer and inner layer; you cut the outer and you have a ridge to lay the piece back on when you close it up. ------------- Gordon '97 Ski Nautique, GT40 |
Posted By: jhersey29
Date Posted: January-04-2021 at 10:09pm
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I cut it at an angle. In one of the video's you can see where I put a layer of fiberglass in to create even more of a lip on the inside Basically cutting it like this shape \ /. |
Posted By: Canuck-Surfer
Date Posted: January-04-2021 at 10:44pm
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I just spent the last hour trying to get these hoses loose. That will have been the hardest part of this project I think. I got the muffler out about five minutes ago and the internals look really solid I was able to get my arm in there and there’s no movement or sound. My only issue is as you suspected, just a small crack along the bottom because the rubber bushings we’re not existence between the muffler and the hull. This will be just a small fibreglass patch and the addition of some rubber on the bottom and I’ll be golden! ------------- 1996 Sport Nautique GT40 EFI |
Posted By: jhersey29
Date Posted: January-05-2021 at 10:16am
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If you got the muffler out with out taking off the risers then you should consider looking inside the exhaust hoses with a flash light. They are supposed to be firm not squishy and flexible. Check for blisters inside the hoses from a prior over heating issue. If you have blisters you should replace the hoses. Also look for any blockage in the 4" hose that may have caused back pressure. Sounds like you just wore through the muffler vs blowing it out. When patching I would try to get a sheet or 2 of fiberglass on the inside as well. That should lessen the pressure on the outside repaired area. |
Posted By: Canuck-Surfer
Date Posted: January-05-2021 at 10:25am
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The area that wore through was the highest spot on the bottom surface of the muffler. It had also worn through the paint on the hull. There was no rubber backing like they were supposed to be I guess. I’m not sure why you would ever have to take the risers off to remove the exhaust system. You just have to do it the right way wink wink ;). I put some soap on the exhaust tubes coming down from the risers and then use the heat going to heat up the rubber sleeve that connects them to the muffler. I used a screwdriver to break the bond between the hose and the pipes and then I used a oil filter bite wrench in the middle of the rubber hose to twist it back over the Exhaust hose. It was tedious but it worked just fine. I just rebuilt the engine for spring so all of my gaskets and bolts on the risers are brand new and I’m sure would’ve come loose but I didn’t want to replace gaskets again. ------------- 1996 Sport Nautique GT40 EFI |
Posted By: jhersey29
Date Posted: January-05-2021 at 10:40am
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You got lucky on how they/you cut your hoses. Some them are cut longer and there just isn't enough room to push them up on the risers and slide the muffler to the rear. Sounds like your on a good track. Good luck! |
Posted By: Canuck-Surfer
Date Posted: January-05-2021 at 10:58am
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Good point. Mine are pretty dang short. They barely sit 2 inches on their respective fibreglass pipes and just barely enough for double hose clamps to seal. ------------- 1996 Sport Nautique GT40 EFI |
Posted By: Up North
Date Posted: March-15-2021 at 12:28pm
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Resurrecting this old post again, I also have an issue with the hull hugger muffler leaking in my 97 Nautique. I pulled it out of the boat earlier this winter and am about ready to fix the leak, which is located on one spot on the bottom of the muffler where it was rubbing against the hull (the rubber pad came out). Looking at this post yesterday, and reading about the loose baffle issue, I shook my muffler and noticed a slight rattle. After reaching in, I am able to grab whatever is inside toward the middle (assuming this is the baffle), and it does move about 1/8" (very slightly), back and forth toward the ends of the muffler body. The question I have is, should I mess with cutting a hole in the muffler to secure it completely, or just glass the worn spot on the bottom. For some reason, I am not able to open the link from the post earlier this year to see the pictures, and it isn't completely clear to me if a tiny amount of movement inside the muffler for the baffle is ok. Thank you in advance for any information! ------------- 96 Nautique 97 Nautique |
Posted By: jhersey29
Date Posted: March-15-2021 at 12:53pm
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The video's are still active and shared. Try a different browser. I wouldn't cut in unless you are really annoyed by the chatter sound. You might be able to reach the broken area via the inlet and outlet ports. Find someone with small hands and use gravity as your friend. I'd find away to watch the videos before doing anything. I'd also consider buying a new muffler. They still produce them. |
Posted By: Scrawford
Date Posted: March-15-2021 at 1:36pm
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I respectfully disagree, you should absolutely repair it as it will get worse. This is much easier than it may seem. Get some glass and resin from the local auto supply, plus a ton of degreaser. 1. Cut a hole out on one side using a vibratory cutter. 2. Soak the muffler in degreaser. Trust me, you can't use too much. I didn't fully degrease mine so had to do it twice. 3. Repair the loose part inside using glass and resin. Remember, it doesn't need to pretty but you do want it clear of the air movement to prevent obstruction. 4. Install the piece you cut out and secure with fabric and a wet coat of resin. Feel free to PM if you need anything else. ------------- Eric 97 196 Closed Bow |