Smoke from exhaust flange

[MightyMike]

Hello, all.

We noticed exhaust smell last year, but could never trace the source.

This year after launch, with the boat all opened up we were able to spot smoke coming from the area of the exhaust flange. A little smoke at idle, more smoke when running harder.

This is our second year with this boat, so we don't know the history. The hot pipes look like they've been around a while. They are rusty but don't appear corroded, at least on the outside.

I have two questions:

1. Is there any chance this could be a failed gasket instead of pipe? I think I know the answer, but hope springs eternal.

2. The metal water muffler looks as rusty as the pipes. Is it a best practice to replace both at the same time? That dramatically increases the cost of this whole operation, but I am wondering what the best course of action is.

Thanks for your help.

[Al Schober]

The hot pipes are on borrowed time after 7 years. Recommend you unwrap yours and see what's going on. Might just be a gasket, but I doubt it.
New pipes are not expensive - 1 1/4" NPT black iron.
If it breaks while on a cruise, you'll have to have it fixed at a marina. If they do it right, they'll use stainless. Parts and labor will be $1000 (ballpark) plus any needed tow.

[MightyMike]

That's my thinking as well. Talked to previous owner who said they are 10ish years old.
That is bad news for my poor son-in -law who will be tasked with removing the flanges bolts.

I am not planning to change out the water lift muffler unless I learn here it should be replaced.

[roadnsky]

I am not planning to change out the water lift muffler unless I learn here it should be replaced.

This is, however, a really good time to give it a detailed check over and at minimum fill it with vinegar and let it sit overnight.

[Administrator]

Probably doesn't need to be said, but as a first responder, I'm compelled.

Remember. that "smoke" can kill.

Bill

[JOHN COOKSON]

If the flange bolts put up a fight try starting the engine, run it up to operating temperature, then have a go at loosing the bolts while the engine is running. The heat + vibration will help the bolts to loosen.
Be mindful of carbon monoxide and hot exhausts while doing this.
Do not try to use an open end wrench. Impact + torque at the same time will give you the best shot at loosing the bolts.
Consider using studs rather than bolts when you replace the current system.
Good luck.

TRUE GRIT