Exhaust leak

[SubtoSail]

I’ll get right to it: I have an exhaust leak that I now think is a bigger problem than I did this morning.

I’ve had a leak at the exhaust flange gasket for some time and finally got around to fixing it. The old gasket stuck a bit and there were some chunks left on the pipe flange. I sanded it smooth as best I could.

Bigger problem is the state of the mating surface on the manifold. It’s uneven and somewhat deteriorated where the leak is. I did what I could sanding and installed a new gasket. Needless to say it is still leaking.

Is there anything short of a new manifold that could solve this? Something crazy like two gaskets, some type of putty?

Pictures are best so I took some. Last one is with new gasket installed, leak is on the lower port quarter of the flange.

Our temporary solution was to leave the cockpit seat on that side open with the motor running, the seat is right above the exhaust pipe. We sail primarily in a bay, using the motor for mooring and anchoring. Rarely do extended motoring. Our CO alarm in the cabin has never gone off.

Any advice or experience you could share is greatly appreciated.

-Joe

[roadnsky]

Hey Joe! Good to hear from you.
and... so apropos on MEMORIAL DAY too.

I assume you're still in Kaneohe?

I remember that exhaust leak from my visit last August.
I wonder if you could use some JB Weld to build up the area and then sand down to smooth? Cheap fix?
I'd also suggest using some High Temp gasket sealer (Permatex)

Of course, if you have the boat bucks you could replace the manifold and be certain.
As Neil says, "Cry once..."

[Ando]

And speaking of Neil, he let me borrow some of this graphite paste to put on the gasket between the manifold and exhaust. It worked well, but I don’t have the same degradation on the manifold. It might do the job for your issue despite the wear on the manifold side. Not sure.

[lat 64]

JB weld is epoxy. I don't think it would hold up to the high temp at that joint.

For a temporary patch, I think an actual muffler repair kit from an auto parts store would be better.
Perhaps retort cement from a fireplace retailer would help. Google Rutland Stove and Gasket Cement
It comes in a tube that fits in a caulking gun. I have had good results in wood stoves with it fixing broken firebrick.
This is just for temporary, not a substitute for new.

I do think that flange could be remachined.

Russ

[ndutton]

I would consider the graphite paste a thread sealer, not a gap filler.

[SubtoSail]

Thanks for the ideas gents. Jerry, still in Kaneohe. The leak started right before you came out. I pulled the exhaust looking for a clog to explain my fouled plugs.

My goal is to not pull the manifold. I’m pretty afraid of that being a huge job that keeps having issues stacking up. If I can even get it off.

I’ll try some power tools to try to get the surface smooth again and get some high temp putty in it.

We were able to get out for a quick sail today and it was perfect. Hope everyone else was able to enjoy the day!