Exhaust tube replacement
Printed From: CorrectCraftFan.com
Category: Repairs and Maintenance
Forum Name: Engine Repair
Forum Discription: Engine problems and solutions
URL: http://www.CorrectCraftFan.com/forum/forum_posts.asp?TID=42768
Printed Date: April-28-2024 at 9:08pm
Topic: Exhaust tube replacement
Posted By: Calisdad
Subject: Exhaust tube replacement
Date Posted: May-10-2018 at 11:38pm
| I tried to tighten up the clamps for the exhaust tube coming from the manifold on my 98 196 with the GT40 engine. Just a couple turns to stop a small leak and I crushed the tube. I have a new one on the way, but I am having a heck of a time removing the old one. Any pointers would be greatly appreciated. |
Replies:
Posted By: KENO
Date Posted: May-11-2018 at 8:31am
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You must mean the rubber is stuck to the fiberglass and giving you a hard time. Have you tried a heat gun to soften up the rubber and worked a screwdriver around the joint? Since you have a new one on the way, why not cut the tube so you can wrestle things around better You could take the riser off the manifold too, but that might create a new set of problems if the bolts aren't cooperative, although it would probably go back together a lot easier doing it this way. |
Posted By: Orlando76
Date Posted: May-11-2018 at 10:10am
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Little confused here. By exhaust tube do you mean the hull hugger muffler? That should be the only crushable item. I recommend replacing the hoses as well in which case heat to soften the rubber or an oscillating multi tool works wonders, that’s what I did. ------------- Please support The Cystic Fibrosis Foundation 1976 Ski Nautique 351 Escort 1993 Ski Nautique purple and black 351 HO PCM |
Posted By: TRBenj
Date Posted: May-11-2018 at 10:22am
| Assuming he’s talking about the fiberglass down pipes that started getting used around ‘95. |
Posted By: Calisdad
Date Posted: May-11-2018 at 4:20pm
| it is the fiberglass down pipe that has wore out...the mat layers have separated. The problem is that rubber hose is so stiff I can't pull the tube away. I am going to cut the old one in half and go from there. i was thinking that maybe there was a sequence to pulling those. Much thanks to those who have responded. |
Posted By: Gary S
Date Posted: May-11-2018 at 5:05pm
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Would be wise to change the 20 year old hose too, it has to seal at the end of the riser so that the water swirls correctly as it exits the end of the riser. Will also be easier to manhandle a new hose rather a crusty old one. Taking the riser off as stated on the other site is an option but most likely the bolts will break off in the lower manifold creating a whole nother set of problems..... ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=1711&sort=&pagenum=1&yrstart=1966&yrend=1970" rel="nofollow - 69 Mustang HM SS 95 Nautique Super Sport |
Posted By: Terp
Date Posted: May-26-2018 at 6:28pm
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Bringing this back up to the top as I'm having an issue with the same system. While winterizing last fall, I loosened the screw clamps connecting the flex pipe to the risers and fiberglass exhaust pipes on both sides, thinking if I removed the rubber flex pipe it would give me better access to the drain plugs on the exhaust manifolds. Well the rubber flex pipe wouldn't budge on either side so I retightened the clamps. I only went as tight as I could with a screwdriver as I was concerned I might overtorque them with a wrench. I put the boat in the water yesterday for the first time this spring and now I have leaks on both sides from the lower portion of the flex pipe where it meets the fiberglass exhaust pipes. There's no evidence of leaks where the flex pipe meets the risers. I've tried repositioning the clamps, retightening, even added a third clamp on the starboard side as it was leaking much worse than the port. Nothing has resolved the problem. Any suggestions or advice is greatly appreciated. ------------- '96 Ski Nautique '90 Boston Whaler Montauk |
Posted By: 8122pbrainard
Date Posted: May-26-2018 at 6:58pm
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John, I have a feeling the only way to solve the leaking is to completely remove the rubber exhaust hose, clean up both the inside of the hose and outside of the risers and the fiberglass tubes. With time, the rubber I'm sure has gotten real stiff making it hard to get a good seal so I would reassemble using some sealer such as Permatex 2B. It's non hardening and waterproof. ------------- /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: Gary S
Date Posted: May-26-2018 at 9:06pm
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Boat is going on 21 years old,I think you need to bite the bullet and just replace the hoses. The 3.5 PCM risers need to fit well at the ends,at the arrow below, to "swirl" the water as it exits the riser. Going to be hard with old hard hoses. Good news though the hoses are not wire reinforced,at least they are not on mine because the muffler is so close to the engine I guess it's not needed. http://imgbox.com/BQOjUqul" rel="nofollow">  ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=1711&sort=&pagenum=1&yrstart=1966&yrend=1970" rel="nofollow - 69 Mustang HM SS 95 Nautique Super Sport |
Posted By: Terp
Date Posted: May-26-2018 at 10:31pm
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Thank you Pete. I'll give that a try tomorrow. Besides heating the rubber flex pipe, are there any other tricks to getting them to move? In the fall I couldn't get them to budge at all, although I had not heated them. They were warmed up pretty good today when I was trying to solve it on the lake and they were still very stiff and immobile. I was wondering if maybe I just need to replace them Gary. They look great from the outside, no dry rot, bulges, etc. May have no choice but to cut them off if they won't budge. ------------- '96 Ski Nautique '90 Boston Whaler Montauk |
Posted By: gun-driver
Date Posted: May-26-2018 at 11:29pm
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I have in the past used a thin screwdriver and worked in under the pipe. Then stick the straw of a can of WD-40 in next to the screwdriver and spray. Do this all the way around along with heating. Then I use the screwdriver to break the seal by prying and stretching the rubber a little. Obviously when doing this on the fiberglass side more care must be taken. I like to use (green) waterproof grease on both the inside of the pipe and the manifold or muffler when reinstalling. Makes sliding things back together easier and it seems to make it easier to take apart the next time. Good luck I'll be down DCL last week of June if you're around give me a shout. |
Posted By: MrMcD
Date Posted: May-26-2018 at 11:45pm
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It was mentioned already but take note those hoses are big and stiff as a board. Warming them does help and also make a strong mix of water and dish soap, I use dawn, wipe both the hose and your manifold with the mix of warm water and dish soap and it helps slip them together. The dish soap will work like grease to help slip them together. Dish soap will wash away and not hurt your hose. If you use any kind of petroleum grease product it will rot your hoses. Heating the hose could be done by the sunshine on a hot day or a hair dryer/heat gun to get them warm and will help assemble the parts. If they are cold you will not succeed, they will be too stiff. ------------- |
Posted By: gun-driver
Date Posted: May-27-2018 at 4:40am
Been using waterproof bearing grease to lube the hoses for over ten years now and have not noticed any ill effect on the rubber. |
MrMcD wrote:Posted By: MrMcD
Date Posted: May-27-2018 at 5:58am
|
I have seen many automotive rubber hoses rotted, usually caused by oil leaks on cars. I spent the 80's working for a rubber company and they taught us to avoid rubber and any oil or grease. If you spilled oil or grease on the rubber hoses you are supposed to wash it off right away to avoid damage. The rot is not immediate but the hose with oil/grease exposure might last 5 years while the non greased hose may last 20. On radiator hoses in cars the soft rubber could rot in 1 year if exposed to oil. Silicone based grease should not affect the rubber. That is the reason you use a silicone based grease when working on brakes, Silcone based grease can lubricate the sliders but will not affect the rubber on the pistons or brake cylinders. Petroleum grease would cause it to rot and fail early.. Fuel lines are blended to avoid the rot petroleum products cause using products like EPDM a blended rubber that can avoid the petroleum rot but you still don't want to leave oil or grease on these hoses. I have never had an issue using the warm soapy water. We put new Marine 3" hoses on my brothers 460 last year and it made the job much easier. ------------- |
Posted By: gun-driver
Date Posted: May-27-2018 at 8:30am
| I'd doubt that a boats exhaust hose is exposed to gas fumes and oil is the same compound of rubber as rubber vacuum, heater and rad hoses of the 80's |
Posted By: KENO
Date Posted: May-27-2018 at 8:44am
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[QUOTE=MrMcD] I spent the 80's working for a rubber company /QUOTE] Doing your part to help control the world's population 
|
Posted By: gun-driver
Date Posted: May-27-2018 at 9:57am
Guess to many people used petroleum products with their rubber products now look at the mess we’re in. |
Posted By: Terp
Date Posted: May-27-2018 at 1:29pm
|
Great info guys, thank you. Started to remove old hosing this AM. Looks like the clearances between the risers and fiberglass pipes are fairly tight. Thinking I may not get the upper sections of hosing off without removing the risers but I'm hesitant to do that for fear of shearing a bolt or two or three. While there is no leaking at the hosing connecting the fiberglass exhaust pipes to the muffler, am I better off removing / replacing them to gain the clearance or is it a crap shoot either way? Or is new hosing generally flexible enough to squeeze through the gap between the riser and pipe? ------------- '96 Ski Nautique '90 Boston Whaler Montauk |
Posted By: Terp
Date Posted: May-27-2018 at 4:40pm
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Pete, would you suggest I use the Permatex even if I'm installing new hosing? ------------- '96 Ski Nautique '90 Boston Whaler Montauk |
Posted By: Calisdad
Date Posted: May-27-2018 at 7:12pm
| I had about two inches of hose that was on the riser after loosening all the hoses and moving the hoses back as far as I could. I just heaved on the sob and pulled it away. I used a new hose that I trimmed two inches shorter and put it all back together. I really don’t know how it was originally put on. |
Posted By: 8122pbrainard
Date Posted: May-27-2018 at 7:28pm
I'm sure there are other opinions out there but, I always like to use some sealer and the nice thing about the 2B is it is non hardening. ------------- /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: Terp
Date Posted: May-27-2018 at 8:19pm
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Ok. I pulled the starboard hose as it had the worst leak. There's a soft spot in the fiberglass pipe, about the size of the thumb pad, above the hose line. I must have tightened the clamp too much. I presume there's no fix for this other than to replace it with a new fiberglass pipe. ------------- '96 Ski Nautique '90 Boston Whaler Montauk |
Posted By: gun-driver
Date Posted: May-27-2018 at 8:34pm
| Do you have an Inverta-Flo if so I fixed mine. |
Posted By: Terp
Date Posted: May-27-2018 at 8:34pm
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Well I didn't think my mood could get worse but it did. Same story, larger area of damage on the port pipe. Anything else I should be looking at / fixing in this area while it's apart and I have the downtime? ------------- '96 Ski Nautique '90 Boston Whaler Montauk |
Posted By: 8122pbrainard
Date Posted: May-27-2018 at 8:36pm
John, Since the soft spot is above where the hose, the repair is easy since you don't need to worry about maintaining the diameter. Just clean up the area by light grinding or sanding and then lay some glass in the area with epoxy resin. ------------- /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: Terp
Date Posted: May-27-2018 at 8:47pm
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I'm not familiar with the inverta-flo Paul. I have the fiberglass hull hugger muffler with two fiberglass pipes feeding into it from the risers and a single larger diameter rubber exhaust hose from the muffler to the transom. It would be a first time for me doing fiberglass repair. Btw. Save for the rare Saturday when I'm in Baltimore I should be around any weekend you happen to be here at the lake. I would enjoy meeting you and having a few beers. ------------- '96 Ski Nautique '90 Boston Whaler Montauk |
Posted By: Terp
Date Posted: May-27-2018 at 8:56pm
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Ok Pete. Just to make sure I'm on the same page. The rubber exhaust hoses covered the soft spots. Both soft spots extend to within 3/4 of an inch of the end of the fiberglass pipe. I couldn't see or feel them until I pulled the hose off the pipe. Would I not have to maintain that diameter since it will lie under the new hosing too? ------------- '96 Ski Nautique '90 Boston Whaler Montauk |
Posted By: gun-driver
Date Posted: May-27-2018 at 8:57pm
The fix is easy, heres some pic's of mine that had a soft spot.    
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Posted By: Terp
Date Posted: May-27-2018 at 9:05pm
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Alternatively, could I cut the fiberglass pipe shorter by about 4" to remove the damaged section then just extend the rubber hosing to make up the difference? It would leave me about a 6" gap between the outlet of the riser and the inlet of the fiberglass pipe. Looking at the fiberglass pipe, it almost appears it has a slight taper or waist to it near the inlet. ------------- '96 Ski Nautique '90 Boston Whaler Montauk |
Posted By: 8122pbrainard
Date Posted: May-27-2018 at 9:25pm
John, OK, before you said "above" where the hose is but now with different wording, I see now it's where the hose clamps. I see Paul responded with his fix. That's exactly what I would recommend. ------------- /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: gun-driver
Date Posted: May-27-2018 at 9:50pm
Without pictures I would say that as long as it's not fractured on the inside you could just grind it and get some fiberglass and smooth out where you're clamps were. You could get something like this at one of Pete's favorite place's to shop  https://shop.advanceautoparts.com/p/bondo-fiberglass-resin-repair-kit-quart-us-can-422/89010800-P?searchTerm=fiberglass+repair" rel="nofollow - https://shop.advanceautoparts.com/p/bondo-fiberglass-resin-repair-kit-quart-us-can-422/89010800-P?searchTerm=fiberglass+repair Or this https://shop.advanceautoparts.com/p/bondo-fiberglass-resin-jelly-kit-pint-us-can-431/89010801-P?searchTerm=fiberglass+repair" rel="nofollow - https://shop.advanceautoparts.com/p/bondo-fiberglass-resin-jelly-kit-pint-us-can-431/89010801-P?searchTerm=fiberglass+repair as long as the tube is just dis-formed if it's like mine I would repair it right. |
Posted By: Terp
Date Posted: May-27-2018 at 10:34pm
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Yeah Pete, sorry about that. I figured the way I worded it the first time wasn't clear. I will try to repair this using Paul's method. Thank you for the advice. Paul, is that an overlay (with the Lowes logo) on the PVC pipe? If so, what is it and is it supposed to keep the epoxy from bonding to the PVC? The damage to my pipes appears less severe than yours. ------------- '96 Ski Nautique '90 Boston Whaler Montauk |
Posted By: gun-driver
Date Posted: May-27-2018 at 11:10pm
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It was just window tape to help keep the resin from sticking to the pipe. I think it was just some thin wall drain pipe I had laying around. Like I said if it's not delaminated inside you could just grind down the soft spot and reglass the outside. As for meeting up at DCL I usually don't do weekends if I can help it. 
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Posted By: Terp
Date Posted: May-28-2018 at 9:03am
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On the inside of the pipe I can see fractured fibers projecting inward if that's what you mean by delaminated. How long after laying up the repair would you wait to put the pipe into use? I avoid the lake on the weekends as well. I'm usually home several days during the week as well. Text or call me if you want to when you're up, 3013259758. ------------- '96 Ski Nautique '90 Boston Whaler Montauk |