I have a Husqvarna 128LD that I bought a few years ago. the only complaint I had was when you mashed the throttle it took along time to get to full power and it took alittle while to get back to full rpm after hitting something that would cause it to bog down. tried tuning it and it got better but nothing like my old trimmer. found out this model has the catalytic converter. Read on the chainsaw forum about gutting mufflers and modding them. so off the work I went. uncrimped the muffler, removed the cat, bored the ehaust port, and brazed a 5/16 copper 90 fitting in place. I must say obviously it is louder but its accereration is like a chainsaw now. just have to wait till the snow melts to find some grass to see how it performs.
Stock muffler with the spark arrestor and deflector removed showing the 3/16" stock exhaust hole.
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Once the muffler is uncrimped the cat simply slides out.
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The exhaust hole is reamed to 7/16 inch and the copper fitting ready for brazing.
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The muffler reassembled, less cat, and new exhaust port installed on the trimmer.
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Stock muffler with the spark arrestor and deflector removed showing the 3/16" stock exhaust hole.
View attachment 286617
Once the muffler is uncrimped the cat simply slides out.
View attachment 286618
The exhaust hole is reamed to 7/16 inch and the copper fitting ready for brazing.
View attachment 286624
The muffler reassembled, less cat, and new exhaust port installed on the trimmer.
View attachment 286625