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adhesive on manifold v riser?


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looks like there was a blueish adhesive used on the manifold to riser (elbow) gasket on the oem build.

adhesive was used on the riser side of the gasket.

i pulled manifolds off to insure i wasn't getting thin (at 1400 hours).

all looks ok. now it's time to re-assemble.

what adhesive? go w/o adhesive? perhaps the same black/hi-temp rtv used on the engine to manifold interface?

i'm sure i can get by w a wild a$$ guess but i'd rather do it right.

thanks for the help.

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you should not need any sealer between the gasket and the manifold/riser. You shouldn't have RTV between the manifold and engine by any means. Use the correct gaskets in both places and you will be fine. Make sure you get all the old gasket off. Also make sure that the surfaces are flat. If you use any scotch pads etc, be VERY careful, as they will remove metal, and if its not flat, it will leak.

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you should not need any sealer between the gasket and the manifold/riser. You shouldn't have RTV between the manifold and engine by any means. Use the correct gaskets in both places and you will be fine. Make sure you get all the old gasket off. Also make sure that the surfaces are flat. If you use any scotch pads etc, be VERY careful, as they will remove metal, and if its not flat, it will leak.

dealer has told me to use black high-temp rtv on the engine to exhaust manifold mating surfaces.

it does not use a gasket.

there was not a gasket on the oem build. just the rtv.

Edited by tvano
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dealer has told me to use black high-temp rtv on the engine to exhaust manifold mating surfaces.

it does not use a gasket.

there was not a gasket on the oem build. just the rtv.

Correct, no gasket manifold to engine. I have used the RTV Black for the riser/manifold connectin in conjunction with the standard gasket and have had no issues what so ever. It fills in any small blemishes/pitting from over the years.

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dealer has told me to use black high-temp rtv on the engine to exhaust manifold mating surfaces.

it does not use a gasket.

there was not a gasket on the oem build. just the rtv.

If there was no gasket from Indmar, then I would do what they did. Interesting. I have not seen any marine motor with RTV in place of a gasket on the exhaust.

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I would use permatex ultra copper sealant on my boat.

Gaskets are the wrong thing to use OEM or not. Gaskets fail where silicone will not.

RTV on exhaust manifolds is a pain in the butt. its messy, and its easy to put too much on. I have not had an exhaust gasket fail in more than 20 years of working on marine engines. My current 14 year old Malibu has a rotted hole in the riser, but the exhaust gasket was perfect when I pulled it. and its never been off the motor since it was new.

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RTV on exhaust manifolds is a pain in the butt. its messy, and its easy to put too much on. I have not had an exhaust gasket fail in more than 20 years of working on marine engines. My current 14 year old Malibu has a rotted hole in the riser, but the exhaust gasket was perfect when I pulled it. and its never been off the motor since it was new.

It's only messy if you let a five year old put it on. If your afraid of putting to much on... then dont put to much on. only a very thin layer required. Gaskets do fail ive seen iit happen more than a few times. And by all means do what your dealer recommends.

Edited by Ruffdog
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Correct, no gasket manifold to engine. I have used the RTV Black for the riser/manifold connectin in conjunction with the standard gasket and have had no issues what so ever. It fills in any small blemishes/pitting from over the years.

I did the same. The Permatex Ultra Black is awesome stuff.

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Correct, no gasket manifold to engine. I have used the RTV Black for the riser/manifold connectin in conjunction with the standard gasket and have had no issues what so ever. It fills in any small blemishes/pitting from over the years.

Coincidently, I have been looking for the exhaust manifold gasket for my engine (93 Mercruiser 5.7 L comp ski), and they did not pop out at me when checking exhaust product links on the sites we all use. I have not pulled them off yet.

So, I should stop trying to buy and use only a sealant? You say above "..in conjunction with the standard gasket" so you use both anyway? Or?

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It's only messy if you let a five year old put it on. If your afraid of putting to much on... then dont put to much on. only a very thin layer required. Gaskets do fail ive seen iit happen more than a few times. And by all means do what your dealer recommends.

messy is in the eyes of the beholder. same as gasket failure. Use the correct gasket and put it on right, and it won't fail.

I wouldn't always do what the dealer says, but if thats what Indmar wants, then as I said before, so be it.

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Coincidently, I have been looking for the exhaust manifold gasket for my engine (93 Mercruiser 5.7 L comp ski), and they did not pop out at me when checking exhaust product links on the sites we all use. I have not pulled them off yet.

So, I should stop trying to buy and use only a sealant? You say above "..in conjunction with the standard gasket" so you use both anyway? Or?

1993 Mercruiser 5.7 Ski. Part # 5 in the picture

https://www.mercruiserparts.com/Show_Pictures3.asp?dnbr=17740&ivar=images/COMMON/41011.png&inbr=953&bnbr=180&bdesc=Exhaust+Manifold+%26+Exhaust+Elbow

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Thanks soooo much. Now to use sealant or not ? ;-)

Your call. Its totally not needed. Just be aware, that after you run the boat a few times that you should re tighten the manifold bolts. they will loosen as the gasket takes a set from heat cycles. This is the number one reason that people get what they think is a gasket failure. Tighten from the middle bolts out, so do the bolt by cylinder #3 than 5 than 1 than 7. Repeat on the other side 4 than 6 than 2 than 8.

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Your call. Its totally not needed. Just be aware, that after you run the boat a few times that you should re tighten the manifold bolts. they will loosen as the gasket takes a set from heat cycles. This is the number one reason that people get what they think is a gasket failure. Tighten from the middle bolts out, so do the bolt by cylinder #3 than 5 than 1 than 7. Repeat on the other side 4 than 6 than 2 than 8.

Sorry tvano for the hijack.

zone5--awesome tfor me to know now (and all future). Printed and in her book.

Regarding the gasket to the riser (original tvano post), do you use sealant?

I like the idea of tightening for my use, i.e., allows me to more easily and quickly check out the manifold internals (seawater boat), and then simply slapping on a new gasket and fini ;-) I wish it were that easy for me

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Sorry tvano for the hijack.

zone5--awesome tfor me to know now (and all future). Printed and in her book.

Regarding the gasket to the riser (original tvano post), do you use sealant?

I like the idea of tightening for my use, i.e., allows me to more easily and quickly check out the manifold internals (seawater boat), and then simply slapping on a new gasket and fini ;-) I wish it were that easy for me

I used to use sealer(copper RTV) on Mercruiser riser gaskets as they for terrible for leaking. Merc said to not do it, but I think they came out with 3 or 4 different gaskets to fix the issue and it was never fixed till they redesigned the exhaust.

The gaskets I have for my new exhaust for my Monsoon don't look like they need sealer, but its not going to hurt anything if you use it, and it will make it seal better. It will just make taking gaskets off a pain if you need to do it again. I'd use gasgacinch, not RTV on them. If you run in Salt water, I would use it for sure. Fresh water is not as much of an issue. The most important thing is making sure that both surfaces are 100% clean and flat. You only have a small surface between the exhaust and the water, so you need that to seal. exhaust leaks are not that big a deal, but if teh water leaks into the exhaust and hits the valves, you have big issues.

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Tighten from the middle bolts out, so do the bolt by cylinder #3 than 5 than 1 than 7. Repeat on the other side 4 than 6 than 2 than 8.

I like the idea of tightening for my use, i.e., allows me to more easily and quickly check out the manifold internals (seawater boat), and then simply slapping on a new gasket and fini ;-) I wish it were that easy for me

I'm sure you know this, but just to make it clearer than I did. There are 2 bolts by the front and rear exhaust. so when I say 1/7 and 2/8, I mean to work your way out from the middle. I probably should have said 3-5-1(in)-7(in)-1 (out)-7 (out), and the same for the even side.

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I'm sure you know this, but just to make it clearer than I did. There are 2 bolts by the front and rear exhaust. so when I say 1/7 and 2/8, I mean to work your way out from the middle. I probably should have said 3-5-1(in)-7(in)-1 (out)-7 (out), and the same for the even side.

Consider your above a question, and there are never any dumb ones, the clarity HELPED me.

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I used to use sealer(copper RTV) on Mercruiser riser gaskets as they for terrible for leaking. Merc said to not do it, but I think they came out with 3 or 4 different gaskets to fix the issue and it was never fixed till they redesigned the exhaust.

The gaskets I have for my new exhaust for my Monsoon don't look like they need sealer, but its not going to hurt anything if you use it, and it will make it seal better. It will just make taking gaskets off a pain if you need to do it again. I'd use gasgacinch, not RTV on them. If you run in Salt water, I would use it for sure. Fresh water is not as much of an issue. The most important thing is making sure that both surfaces are 100% clean and flat. You only have a small surface between the exhaust and the water, so you need that to seal. exhaust leaks are not that big a deal, but if teh water leaks into the exhaust and hits the valves, you have big issues.

A lot of info comes out. Yea! We absorb, we decide.

Since mercruiser manual said use quicksilver perfect sealant, does anyone know if that (or equivalent?) is easier to use/remove etc. vs. other options (e.g., gasgacinch above)?

And, if this stuff is easy to use,etc., maybe to apply on manifold too is a safer option to using nothing...

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Since mercruiser manual said use quicksilver perfect sealant, does anyone know if that (or equivalent?) is easier to use/remove etc. vs. other options (e.g., gasgacinch above)?

And, if this stuff is easy to use,etc., maybe to apply on manifold too is a safer option to using nothing...

The Merc stuff is their brand of gasgacinch. very similar to varnish in appearance, just a bit thicker. Manifold gasket "should" be an aluminum looking dimpled material. It compresses which is how it seals.

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The Merc stuff is their brand of gasgacinch. very similar to varnish in appearance, just a bit thicker. Manifold gasket "should" be an aluminum looking dimpled material. It compresses which is how it seals.

Roger! and thanks.

Like most say, this is a great site for getting to know and love your bu.

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