Better compounds containing nitrogen can become an explosive. Like if the Techron managed to soak through the carbon before swelling up. Creating a chamber. Apply heat the cleaner expands uses the carbon as a catalyst and you don't want to know the rest of this story
But max dose your gas tank for the remainder of the year. This will help remove the carbon and it will be a lot of snot in the muffler.
I had to learn all this stuff from scratch. My Honda experience goes back to the days of the 50, and the 305. Almost 60 years ago. Doesn't make me an expert merely pre-manual days.
Since this is resolved here's a generator story. Belt driven with divorced generator with brushes. External voltage adjustment knob.it was the days of normal transformer battery chargers. I used the knob to fine tune the charge rate. The generator had brushes that used to hang up when parked in a beach.
A replacement loaded brush holder cost %21,00
Do forty years later when I read in this thread how much a Honda muffler cost I winced
Original Poster: I tried brake cleaner.. not so effective Carb cleaner.. better than brake cleaner it seemed.
This carbon seems resistant to cleaning.
Then I fired up my grill and tossed in the muffler. Turned it over a few times. I think the hotter you get, the more carbon gets burned off. Dont think my grill was extremely hot. When i was done, i tapped the muffler all over.
Also picked up some rubber corks at the hardware store. This so i could fill the muffler with carb cleaner. But also you can drill a little hole through the cork and put the little red straw through it. Then you can blow canned air through it if you donโt have a compressor available.
The cork/can thing also allowed me to bust through the initial full blockage.
Have you tried compressed air, maybe while tapping the muffler on a hard surface?
There's also AC Delco upper engine cleaner which is used to dissolve carbon build up in the combustion chamber. If whatever is blocking your muffler is carbon-like, that may work.
