DannytreeLLC
ArboristSite Member
Really?
MS250 Mods
- Thread starter Ittybittyfitty
- Start date
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AmateurSawer
ArboristSite Operative
If I should want to do a muffler mod.,how much retuning should I do? Mine still has caps on the adjustments.
You will probably have to get rid of the limiter caps, I had to on mine.
Most saws benifit from their removal, for instance a friend's Husqvarna 455 is so rich you can't tune it lean enough with the caps in place.
With with my ms250 the opposite was true, before the mod you had to tune it stupidly rich because the stock restrictive muffler kept so much exhaust gas in the cylinder it leaned it out. After the muffler mod it flowed so much better I had to lean it out one full turn both high and low speed because it now scavenged the cylinder like it was supposed to.
Understandable when the muffler originally had an exit hole the size of a pencil eraser.
Most saws benifit from their removal, for instance a friend's Husqvarna 455 is so rich you can't tune it lean enough with the caps in place.
With with my ms250 the opposite was true, before the mod you had to tune it stupidly rich because the stock restrictive muffler kept so much exhaust gas in the cylinder it leaned it out. After the muffler mod it flowed so much better I had to lean it out one full turn both high and low speed because it now scavenged the cylinder like it was supposed to.
Understandable when the muffler originally had an exit hole the size of a pencil eraser.
SteveSr
Addicted to ArboristSite
For reference the original pre-EPA 025 (predecessor) had a 0.865" x 0.624" exit hole which would be a good place to start. Or just find an old 025 muffler to replace it with. If you decide to do any sawing or grinding you have to be ABSOLUTELY CERTAIN that you can and do remove any filings/cuttings from the can. All it takes is one to get sucked back into the engine and you're toast!
The sketch below shows 2 different versions of the 1123 series muffler. The latest version has an even smaller hole. There may be others as well.
The sketch below shows 2 different versions of the 1123 series muffler. The latest version has an even smaller hole. There may be others as well.
Ittybittyfitty
ArboristSite Operative
Thank you for that tip. I'm going to look for an 025 muffler. I'm not confident in my abilities or lack thereof to do the mod myself and be sure to get the crap out.
SteveSr
Addicted to ArboristSite
You need to find a muffler where the seam is not rolled. That way it comes apart to clean it out after any machining.
