Weedeater SST25 Trimmer Muffler Mod - Very Pleased With Performance Increase

[LFEngineering]

Oh look another muffler mod thread.... Seriously though I just wanted to say how impressed I was with the performance increase of my 25 cc Weedeater string trimmer. I've done a few other muffler mods to chainsaws with slight power enhancements, but this one was night and day. It worked great for around the yard trimming, but when it came to leveling the 12-14" weed / grass combination in the Blueberry patch I knew something had to be done. The motor lacked power, even taking a 1 or 2 inch cut on each swing it just didn't have the power. I tried adjusting the carb, but that didn't change anything. I split the seam on the muffler, ripped out the catalytic mesh, opened up the baffle,added a 3rd outlet louver and welded it back together. After a quick carb tuning it was like a completely different machine. Back down in the blueberry patch I could take full 6" cuts with little to no hesitation.

 

[FergusonTO35]

I have a Poulan BC2400 which is an older version of that machine. After 13 years of extensive use I finally had to put a new carb on it this year, the first actual repair it has ever needed. Mine was sans catalyst from the factory and has always impressed me with its performance. With good line it doesn't give up much to my Echo SRM-225.

 

[LegDeLimber]

Muf mod, carb tune (with full lookover of fuel system)
and good cleaning & relubing of the drive line
usually does wonders for a weedbeater.