Exhaust tube exploded... Need help

[Connor]

Hey guys, posting this for a buddy of mine with 09 210. He recently bought the boat and has had many issues already. Yesterday, he launched the boat and took off towards our normal spot and he heard a noise, opened up his motor hatch and saw that his exhaust tube had exploded (see pic). He immediately thought maybe it was old or faulty so trailered his boat, ran to the store and grabbed a new one and installed it. relaunched the boat and took off again. The new hose exploded at about the same distance away from the dock as the previous. Any ideas what could be causing this or at least where to start.

Disclaimer- I was not with him yesterday and these are just pics he sent me. He told me the water is pumping out of the motor correctly before the tube. I told him it sounds like a clog and he said he cannot find anything in there and it seems clear... I just feel bad because he is not getting the true Nautique experience so far...

[bchesley]

If he is not getting any water out of the end of the manifold then that is the problem. If there is water coming out of the end of the manifold then the muffler has failed internally. Rubber hose does not like heat for very long. I have smoked a hose like that before and it was due to lack of water.

[azeus17]

Because I was a little confused after reading that, let me try to simplify it. After he blew the hose, water should have been coming out of the exhaust riser and filling his bilge. If it wasn't that is a problem. If it was, then the problem probably lies in the muffler itself (some sort of blockage). I have heard of the fiberglass mufflers blowing out as well.

Please correct me if that is not what you were trying to say, bchesley.

[Connor]

Yeah, I agree with both of you. The motor is pumping water correctly because his bilge quickly filled up on the way back to the dock. I believe the problem must lie in the muffler... Weird thing is it must be one side because the other exhaust tube is fine

[s_kelley2000]

I wonder if one of the internal baffles of the invertaflow muffler let go and is blocking the outlet from one side. Or perhaps a previous overheat melted some of the internals and created a blockage. Without X-ray vision I am not sure how to determine that for sure without cutting an access hole. you might be able to reach your hand in but not sure you could tell what was up. If that is the problem the baffle can be removed or glassed back in place and then re-glass the access hole. I'm not sure what else it could be but if it were me I'd still have a little bit of a hard time cutting into it on a hunch. Issues like this and leaky mufflers sure make me happy that there was no room for mufflers on the 502s. Good luck and hopefully he gets back on the water soon.

[azeus17]

I am not sure which would be more cost effective, but you could just remove the invertaflow, add a Y pipe and run without a muffler. If there was a blockage in the invertaflow, though, it seems like it would have blown before the tube did. Have heard several stories of the invertaflows blowing out.

[s_kelley2000]

Hmm that is a good point that you would think the invertaflow would blow before the exhaust tube would. I imagine the glass is pretty thick and possibly reinforced with something strong right around the area where the exhaust tube connects so that you can crank down the hose clamps without collapsing it. If the blockage is right at the beginning then maybe the hose becomes the weak point. If that was the case it should be pretty easy to see or feel the blockage. I am not sure on the cost of the Y pipe but it would certainly be cheaper than replacing the invertaflow...and make that boat much louder.