Removing Corsa Mufflers Need Help Removing or Gut Them?
 

Our boat is at Marine Tech Concepts getting the 250 hr top end refresh done to the 525 EFIs. "While your in there" I was going to have Jeff remove the factory installed Corsa 12650 mufflers and replace with 4" straight cut tips with internal rubber flapper. MTC relayed to me the mufflers were installed with an extreme bonding material, 5200 I believe he said? The muffler they tried to remove would not budge at all and the tech is warning there might be gel coat damage if going any further. Have any of you experienced this disassembly issue? Is this a Formula related problem or related to other brands? If the mufflers cannot be removed has anyone ventured in cutting out the core? Any help or information is really appreciated!
[ATTACH=CONFIG]521748[/ATTACH][ATTACH=CONFIG]521749[/ATTACH][ATTACH=CONFIG]521750[/ATTACH]

Well, I'm here to tell you that I just used regular marine grade silicon on my tips, and it still took hunks of the gel coat off when I removed them. Not an uncommon problem, I'm afraid. Maybe talk to someone in the window glass business to see if there is some kind of cutting tool you could work in there between the tip and the hull to cut through the silicon. At the very least, try to scribe around the outside of the tip so that if any gel comes off, it will be limited to the portion under the tip that will hopefully be hidden by the replacements.

I have a set of those tips, and it is my understanding that gutting them is a lot more involved than just removing the bolts and screws for the baffles. Those things are welded together, and everything is stainless steel, meaning that it has a tendency to case harden on you when you grind or cut on it with most tools. Probably not an easy deal to do when installed. I would do a search on the forums - many people have gutted these things, might find some good suggestions on the best way.

Not sure exactly how restrictive they are. Buddy of mine has them on a boat that was running a ProCharged HP500, and he was running in the 80's with it. Never ran it without them to compare. Another friend had a slightly smaller set behind an HP465, and put the angled tips with no muffler because he wanted it louder. No speed gain, just more noise. Just FYI.

Great info, thanks for the reply

I gutted mine and it was a *****.... Used a die grinder to remove the welded areas but it went pretty quick. The round piece had to be folded in half to be removed and then the coiled sound suppressor "snake" is last to come out........ If you like it loud then you will be happy! My 502 with high compression and high lift cam and 496 exhaust starts up with a very angry snarl! With a Load on It and rpm, s up around 3,500 it sounds like I have twin big blocks out back! It roars and sure sounds like a big boy offshore machine!

Good info on gutting them. There looks like a threaded rod in the middle of the "plate". Did you cut that off to separate the plate from the baffle assembly?[ATTACH=CONFIG]521761[/ATTACH]

You need to heat the inside of the pipe up from the engine side with just a propane torch. Mine wouldn't budge until About 15 seconds heating the inner pipe they slid right out.

That would be to remove the tip from the hull.

Wrap a ratchet strap around them, hook both ends to the trailer, and slowly crank down on the strap. This will put enough pressure on the tip to pull them away from the hull. You will here it when they start to break free. Just go SLOW.

Would some fishing string work to cut the silicone.... Kinda saw it back and forth if you can get behind it.

Great advice so far, anyone else please post if you have had experience or knowledge of removing these mufflers, thanks again Rob

Thought of this one, like taking a windshield out of a car. The issues are this 5200 is much more than a standard silicone and the way the 3 mounting studs are triangulated , if you could get behind there you run into the studs quickly.

Guitar string is what we always used to remove windshields back in the day. You pull it back and forth to "saw" through the sealant. Even though you might hit the studs, you may be able o get enough of it off to minimize gelcoat damage. Maybe use this method combined with a few of the others to get them off.

Are you sure they used 5200? That is generally something you use for a permanent installation, like a swim platform that is below the waterline. 4200 or just regular marine silicone is usually fine for thru hull tips. Also, if Formula didn't already do it for you, now would be a good time to get some resin and glass in the openings where the tips pass through the transom. That way, if you ever do develop a leak hear, the water will pass relatively harmlessly into the bilge instead of wicking into the core of your transom and rotting it out.

On the 5200 or 4200. Jeff from MTC called Formula factory and for a span of a few years they used 5200 on the mufflers, early to mid 2000's and my boat falls into early 2005 assembly. They have stopped using the 5200 on the mufflers just for the fact of removal, that's a no brainer. Now we have to get a solution to their bad choice, not the end of the world just trying to get this done without damaging the boat. Thanks for your suggestions.

Try this also http://www.marineformula.com/

Never used it, but heard it works well.

I think I hit the center rod or bolt with the die grinder when I was in there... It was pretty rusty and came apart fast..... I had lots of rust inside and wanted to get rid of everything inside as it was in bad shape..... TBF

Great, I will pass this on to the tech

Rust Inside? Thought these were full stainless steel? For the $ they should be!

I bought my boat with no engine and the exhaust was still in the boat attached to the corsa system..... Obviously the stock 502 exhaust was gone but I was surprised to see rust in the diverters and tips.... I had to replace the diverted valves as there was not much left of them and it seems the pieces that broke off sat for years and caused the rust. But with some work and new parts it all cleaned up well! Salt water is nasty and I am a big believer in using salt away after every use..........

Also, stainless steel is not rust proof but more like rust resistant....I have seen plenty of stainless parts rust but it does take a lot longer......

I am planning to gut my silencer tips on a 28ZX tomorrow with a plasma cutter. I have one tip off and want to see how it does in the shop. I am hoping to do the other 3 while on the boat. Anyone have any experience with this??

Don't do it!!!
You can buy nice non-baffle tips for what you can sell your current ones for. The screw you see in the middle is not holding the structure in. The structure / baffles are welded to the shell. I did it once and will never do it again!

I ended up leaving them on the boat and I did not gut them. Resale value of the part after removal is a very good point.

No experience, but a quick web search lends info on these products:

http://www.marineformula.com/buy.html

http://store.marinebeam.com/unhesive-5200-remover.html

I posted a quick cell phone Utube vid of my exhaust at idle.... search 26ZX idle and it should pop up.... If I need it quiet I can switch to thru prop exhaust..... running at speed around 50 or so you really cant hear the exhaust too good but getting up on plane at slower speed it is pretty mean sounding! TBF

Update. I had 2 separate shops looks at removing the mufflers and both had the same diagnosis, too much 5200 and both said fiberglass repair would be needed. So I did the following. Purchased a few 3 5/8" bi metal hole saws and a heavy duty arbor. Lowe's brand was much more effective than Home Depot's. Burned 4 Home Depot to 1 Lowe's. [ATTACH=CONFIG]543900[/ATTACH] Next I used a 90 degree cutoff wheel and removed the exposed nut and thread [ATTACH=CONFIG]543901[/ATTACH] A 3 5/8" hole saw just fits in the muffler outlets. Using cutting oil and very slow RPM (75-100) on hand drills, I was able to get started [ATTACH=CONFIG]543902[/ATTACH] After I spent a long time on the first muffler I got a system down and averaged 45 Minutes per muffler. Frequent oiling and slow speed was the trick [ATTACH=CONFIG]543903[/ATTACH] The stainless steel is 1/8" thick and a cymbal shaped water diverter was inside [ATTACH=CONFIG]543904[/ATTACH] Inside the mufflers is a coil that when combined with the "cymbal" like diverter route water around the plate that was just cut out. The inlet at the transom to these mufflers is just a shade larger than 3 5/8" so going thru the work of removing the coil is a non-gain in my opinion. Finishing touch is a set of flappers from Hardin Marine [ATTACH=CONFIG]543906[/ATTACH] Would I do it again? On my own boat yes, doing it for someone else, no way.

Rob Looks good. Let us know it sounds. I have removed stock silencers on formulas and is not easy. I usually use air chisel with shim against transom to remove. Have never hurt gel but silencers get damaged easily. I have been running GGB slip in silencers and really like the sound. Kinda like a chambered muffler sound.

Older thread, but wondering if there are any new techniques to gutting these baffled corsa tips?

Faster way this cuts faster
 

https://cimg3.ibsrv.net/gimg/www.off...fd5fe7396d.jpg

Came across this searching for something else. Just use heat and piece of braided fishing line like a worked behind the flanges.