Black chunks when draining exhaust riser

[Matt S]

Sunday I had my 07 Glastron with 3.0L volvo on the hose flush to clean out the lake trip from the day before. All of 3 hours on the motor. When all was said and done I drained the exhaust and to my surprise tons of black pieces that look like pencil lead came out. I had to stick something up in there to get it all out. It was chalky and oily like carbon. I did not get this when draining the block, only the exhaust riser. In addition to this, when the motor is running the bellows was leaking water at the outdrive side (not the transom side).
I called the dealer today and told them about this and they had never heard of this before, were stumped on the bellows leaking, and wanted me to bring it in this Friday; which I am doing for sure.

Obviously the dealer is willing to put off all the people who didn't winterize thier motors (heh) but I figued I'd ask the experts here to see if they've heard of this just for a second opinion. Thoughts?

 

[Don S]

Re: Black chunks when draining exhaust riser

I've seen manifolds come in from Merc brand new with sand in them from the foundry.
But you are doing the right thing by taking it back to the dealer.

 

[housecalls]

Re: Black chunks when draining exhaust riser

I think the little black chunks are a part of volvos process with the manifolds and risers. Brand new out of the box we have to blow them out before we install them.

 

[Matt S]

Re: Black chunks when draining exhaust riser

Thanks guys. I should note that when they showed me how to drain the motor after the demo run (and before they got my money) I don't recall this stuff coming out. It's for sure not going to cost me anything but I always like to be educated.

 

[87baylinercapri]

Re: Black chunks when draining exhaust riser

Sunday I had my 07 Glastron with 3.0L volvo on the hose flush to clean out the lake trip from the day before. All of 3 hours on the motor. When all was said and done I drained the exhaust and to my surprise tons of black pieces that look like pencil lead came out. I had to stick something up in there to get it all out. It was chalky and oily like carbon. I did not get this when draining the block, only the exhaust riser. In addition to this, when the motor is running the bellows was leaking water at the outdrive side (not the transom side).
I called the dealer today and told them about this and they had never heard of this before, were stumped on the bellows leaking, and wanted me to bring it in this Friday; which I am doing for sure.

Obviously the dealer is willing to put off all the people who didn't winterize thier motors (heh) but I figued I'd ask the experts here to see if they've heard of this just for a second opinion. Thoughts?

your exhaust bellows may have 4 tiny holes in them, my do on my 96 3.0 volvo. they looked like they were there from the factory so i went to the dealer, they looked up and grabbed a new exhaust bellow and they too have 4 holes in them, so im guessing thats where the water is exiting while your running it... should be normal.

 

[bjcsc]

Re: Black chunks when draining exhaust riser

You're making the right decision taking it back. Whether it turns out to be a real problem or not is irrelevant. You have to be comfortable with your boat and it's procedures. You've just started a love-hate relationship that wil last for the rest of your life...

 

[AZ_Ron]

Re: Black chunks when draining exhaust riser

I'm new to boats, but have a LOT of experience machining graphite... you mention that these little black pieces look like pencil lead... As most people know these days, there is no lead in pencils any longer... it's all graphite. Graphite is in a class by itself when it comes to withstanding heat. We use it for the nozzles in rocket motors that run between 3000-6200F and it hold up just fine. I'm wondering if maybe it was used in the mold when the cast the risers instead of sand. After having the engine heat cycle a few times, loosened them up. Like I said, I'm a total Newbie to boats... hoping to buy our first one in the next couple of weeks, but from your description, this sounds like a possibility.
Please let us know what the dealer has to say either way!

Thanks!

Ron

 

[Matt S]

Re: Black chunks when draining exhaust riser

It was casting just as everyone described. They pulled an exhaust manifold off the shelf and showed me. It should do that the next few times I drain it, is all. They also said that volvo started putting small holes (as someone else described) in the bellows so it doesn't hold water in there with the outdrive up. They checked it all out, and said "drive it you're fine". Good piece of mind.

 

[AZ_Ron]

Re: Black chunks when draining exhaust riser

Glad to hear you're good to go!!

Ron