Exhaust Manifold Noise.

[FourWinnsLC]

I'm hearing a popping, cracking... Noise at idle. From listening it sounds like its in the exhaust manifold rubber boot area, and you can place you hand on the rubber boots and feel it also.

Cracked exhaust manifold????, any help would be appreciated.

Thanks,
Mike

 

[FourWinnsLC]

Re: Exhaust Manifold Noise.

I guess i should add its a 1996 fourwinns sundowner, 5.8 volvo penta

 

[tpenfield]

Re: Exhaust Manifold Noise.

A Youtube video of the noise from a few different angles would be good.

 

[bruceb58]

Re: Exhaust Manifold Noise.

Almost sounds like the exhaust shutters bouncing around.

 

[JON NEELEY]

Re: Exhaust Manifold Noise.

Did you resolve this issue? My four winns was doing the same thing. What I found out when I removed the exhaust from risers was that the exhaust elbow was rubbing the riser. wouldnt know it unless I took the rubber boots loose and the elbow off. Can clearly see where it was vibrating. Simple adjustment of the eblow and it fixed the problem. While in there that deep I pulled the flapper our of Y pipe. Other flapper had already bit the dust and fell down in exhaust port. Dug it out with a coat hanger..Pain in neck!!! Volvo says we no longer need flappers since they will rot and fall down Y pipe anyways

 

[bruceb58]

Re: Exhaust Manifold Noise.

What I found out when I removed the exhaust from risers was that the exhaust elbow was rubbing the riser.

Could you clarify? As far as I know, exhaust elbow and riser mean the same thing.

 

[JON NEELEY]

Re: Exhaust Manifold Noise.

Sure thing buddy, actually this is easier, where you exhaust meets your Y pipe, look there. You should see a rounded elbow the size of a softball that will go to your manifolds. Big rubber exhaust hose connects that elbow to the manifold.

 

[JON NEELEY]

Re: Exhaust Manifold Noise.


here ya go bruce

 

[bruceb58]

Re: Exhaust Manifold Noise.

Yes, none of the metal exhaust parts should ever be touching. Someone before you installed that incorrectly.

 

[JON NEELEY]

Re: Exhaust Manifold Noise.

yes Bruce, I would tend to have to agree with you and the things made a terrible vibration that drove me insane!!!!

 

[bruceb58]

Re: Exhaust Manifold Noise.

I didn't think it was physically possible to position them so that they touched. Guess not.

 

[FourWinnsLC]

Re: Exhaust Manifold Noise.

Almost sounds like the exhaust shutters bouncing around.

After reading many many posts here on Iboats I was thinking the same thing, I hope its it.

 

[FourWinnsLC]

Re: Exhaust Manifold Noise.

Did you resolve this issue? My four winns was doing the same thing. What I found out when I removed the exhaust from risers was that the exhaust elbow was rubbing the riser. wouldnt know it unless I took the rubber boots loose and the elbow off. Can clearly see where it was vibrating. Simple adjustment of the eblow and it fixed the problem. While in there that deep I pulled the flapper our of Y pipe. Other flapper had already bit the dust and fell down in exhaust port. Dug it out with a coat hanger..Pain in neck!!! Volvo says we no longer need flappers since they will rot and fall down Y pipe anyways

I Actually have it at the repair shop right now, just because I dont have any time to look at it my self. I told the repair shop what i thought was wrong with it, and he goes into saying hes has to check plugs and wires, compression checks..... I'm thinking at this point he seen me coming and its going to cost me big $$$$$ for something i could have done.

 

[JON NEELEY]

Re: Exhaust Manifold Noise.

oh man, not sounding good. I was lost as to what it could be. Took drive off and thats when I found 1 flapper. I replaced gimbal as this was a used boat along with bellows to start my own maintenance schedule. Put it all back together and still had the noise/vibration. Thats when I decided to take exhaust apart and definately a pain to get rubber boots seperated from elbow and sure enough the port side was overlapping the riser elbow and vibrating enough that you could see that it had been doing it a long time and wore the elbow half the thickness at that spot. very simple fix, slide elbow back,tighten crap out of boot and instant quiet motor!! oh and beat the flapper out with a thick long dowl and hammer and coat hanger to fish it out.

 

[FourWinnsLC]

Re: Exhaust Manifold Noise.

Ok, Marina was taking to long and I was getting withdraws from my boat, so I went and got it and wanted to check out the flappers in the exhaust like several of you suggested. And you were right.

But what we found was the actual flapper needed replaced ($25.00 new with bushings) but the biggest issue we ran into was the exhaust pipe was wopped out from the rod the flapper sits and pivots on. and ended up having to drill new holes 45 degrees from the original for a new rod. This has to be exact and trying to drill the holes perfect while crunched in the engine compartment like a pretzel was a challenge.

Here's a poor picture of the wopped out hole.

 

[bruceb58]

Re: Exhaust Manifold Noise.

Why not just remove them and be done with it?

 

[FourWinnsLC]

Re: Exhaust Manifold Noise.

Well we went back and forth about replacing them or taking them out. I talked with a marina and they said they recommended replacing. Expecially if you are in rough water.

 

[Thalasso]

Re: Exhaust Manifold Noise.

Well we went back and forth about replacing them or taking them out. I talked with a marina and they said they recommended replacing. Expecially if you are in rough water.

Volvo quit putting them in for whatever reason somewhere around your year of Manufacture. 99 i think

 

[Thalasso]

Re: Exhaust Manifold Noise.

Volvo quit putting them in for whatever reason somewhere around your year of Manufacture. 99 i think

If you don't come of plane to idle fast (which you shouldn't do anyway) or back up hard it isn't going to inject water in the exhaust.