exhaust gasket problem

[daddydoo]

trying to find out the ft/lbs torque specs for the bolts when you replace the exhaust gasket on a 315hp 350 mercmpi(o5)cant seem to find these numbers. thanks

 

[Don S]

Re: exhaust gasket problem

Which exhaust gasket? Manifold to block, riser to manifold ?
Is that the dry joint style manifolds & risers?

 

[daddydoo]

Re: exhaust gasket problem

i just know from last time as the exhaust gasket, the part # is 27-33395, not sure other than that, happened 2 yrs ago, and was fixed by merc mechanic, now i hope to fix myself

 

[Coors]

Re: exhaust gasket problem

Manifold is 25, riser is 12 ft/lbs.

 

[Don S]

Re: exhaust gasket problem

What was fixed 2 years ago? With an 05 engine it would have been brand new. You should have had the dry joint exhaust system on an 05 boat.
What problem are you actually having.
Do you have the serial number of this engine? I can find out exactly what you have.

 

[Don S]

Re: exhaust gasket problem

Manifold is 25, riser is 12 ft/lbs.

Not exactly, in all the OEM manuals the torque for the manifold to engine is 27 ft lbs.

Not sure what your 12 is, but here is the service bulletin on the riser torque for the non dryjoint style risers, and how to install the new gaskets.

http://www.boatfix.com/merc/Bullet/99/99_10.pdf

 

[daddydoo]

Re: exhaust gasket problem

the serial number is ow 392567, its an 05 merc 350 315hp mpi . the exhaust gasket was changed on warranty at 28 hrs by approved merc dealer, have had no other problems till late last fall when same noise ( same side of motor)came about. it slowly is getting louder, bought the part, just have to do the elbow work now.i know its an exhaust gasket, just not sure exactly how to. have a mechanic friend giving me a hand, just wasnt sure the torque specs on bolts. thanks again for all info and help, much appreciated

 

[anthony115merc]

Re: exhaust gasket problem

you do not need to torque the bolts

 

[Don S]

Re: exhaust gasket problem

I think you better take it back to the dealer. If this is on an 05 boat, it should have the dryjoint type exhaust system on it, and it doesn't even use that gasket number you posted.
Now if this was a repower and they went back to the old style manifolds, then that is another thing.
With the dryjoint exhast system, the torque values are also different. So you really need to make sure what you actually have there before starting anything.

 

[daddydoo]

Re: exhaust gasket problem

according to merc, this is the right gasket, had them double check for me went on mercs site and it shows this part and #. will find out in am when i tear into it.

 

[Don S]

Re: exhaust gasket problem

according to merc, thios is the right gasket

Who are you calling Merc.
A dealer can look up your engine by SN alone. And since I am a dealer, I looked it up. Guess what. That is not a gasket used in your engine

Go over to Mercs parts express at http://www.mercurypartsexpress.com/PartsExpress/HomePage/homepage.asp
Then click on "Parts for Mercury Marine Products" > then fill in the SN section with your SN (0W392567) and click continue. Once you get past the zip and dealer BS, click on the dropdown menu next to"Please Select One" and click on Exhaust Manifolds, Elbows,and pipes
Now, look for that Part Number........ You are not going to find it.
You can also put in that part number back where you put in the SN of your engine and search that way. then all you have to do is find your engine.
Sounds to me like your dealer is feeding you a line of BS.

 

[Reel Poor]

Re: exhaust gasket problem

Don the part # he listed in his post above 27-33395 is listed in that diagram. It's the exhaust manifold to head gasket #5, not the manifold to riser #12.

 

[daddydoo]

Re: exhaust gasket problem

yes this is where we found it, part #5, which is part i have and part # is same as i posted

 

[daddydoo]

Re: exhaust gasket problem

thanks reel poor for confirmation, if i am having an exhaust leak from top side of manifold, would this not be the right gasket, its not real loud, just enough to know its leaking and there seems to be no other leaks (sounds or water) anywhere else

 

[Reel Poor]

Re: exhaust gasket problem

The gasket #12 Don is refering to can also leak exhaust, without leaking water. I can't tell you which one is leaking. That would have to be determined by physical inspection.

If the head to manifold gasket is what was changed when the motor was new and is in need of replacement again, I think I would be looking for the cause of the problem. Those gaskets should not keep going out. Both the head and manifold gasket surfaces should be checked to see if they're flat/straight.

 

[Don S]

Re: exhaust gasket problem

Got me how I made that mistake with the part number But I sure did.
Sorry about that :redface:

Reel Poor is correct, if that gasket is leaking again both the manifold and the head need checked for flatness and defects. Those seldom leak.

 

[daddydoo]

Re: exhaust gasket problem

thats ok don, all your help and information has been very helpful, we are human. thanks again, will take apart this a.m. and get it all checked out

 

[daddydoo]

Re: exhaust gasket problem

fixed the problem this afternoon with help from a mechanic friend. it was the gasket i had purchased,no other problems, a quick hour and a bit to do. think if it happens again i will try a metal gasket from the auto side as those merc gaskets look a little frail, thanks to all who helped with info, i appreciate it

 

[Reel Poor]

Re: exhaust gasket problem

If it was my motor I would be wondering why it has had to have the same gasket replaced twice already, especially since the first went out with 28 hrs on it. If it blows out again you need to fix the problem and not the symptom.

BTW, the automotive gaskets will rust.

 

[daddydoo]

Re: exhaust gasket problem

if it goes again, it will definately be getting a thorough check to find out why, hoping just unlucky though